Methods and devices for applying RF energy according to energy application schedules

ABSTRACT

Electromagnetic energy is applied to an object at multiple modulation space elements (MSEs). MSEs are grouped into at least a first subset and a second subset according to a first grouping rule. A first EM energy application protocol is associated with the first subset and a second EM energy application protocol is associated with the second subset. Energy is applied at each of the plurality of MSEs according to the first EM energy application protocol and the second EM energy application protocol. MSEs are grouped into a third subset and a fourth subset according to a second grouping rule. A third EM energy application protocol is associated with the third subset and a fourth EM energy application protocol is associated with the fourth subset. EM energy at each of the plurality of MSEs is applied according to the third EM energy application protocol and the fourth EM energy application protocol.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/759,166, filed on Feb. 5, 2013, which claims the benefit of U.S.Provisional Patent Application No. 61/595,413, filed on Feb. 6, 2012 and61/595,399 filed on Feb. 6, 2012. The disclosures of all of theseapplications are incorporated herein by reference.

TECHNICAL FIELD

This is a U.S. Patent Application relating to a device and method forapplying energy from electromagnetic radiation in the radio frequency(RF) range (hereinafter “RF energy”) to an energy application zone, andmore particularly but not exclusively to such device and method thatapply the RF energy for heating an object in the energy applicationzone.

BACKGROUND

Electromagnetic (EM) waves have been used in various applications tosupply energy to objects. In the case of RF radiation for example, EMenergy may be supplied using a magnetron, which is typically tuned to asingle frequency for supplying EM energy only in that frequency. Oneexample of a commonly used device for supplying EM energy is a microwaveoven. Typical microwave ovens supply EM energy at or about a singlefrequency of 2.45 GHz,

SUMMARY OF A FEW EXEMPLARY ASPECTS OF THE DISCLOSURE

Some exemplary aspects of the disclosure include apparatuses and methodsfor applying RF energy to an object in an energy application zone andmore particularly for applying the RF energy for heating an object inthe energy application zone.

Some exemplary aspects of the invention may be directed towards anapparatus for applying EM energy to an object in an energy applicationzone via at least one radiating element at a plurality of modulationspace elements (MSEs), defining adjustable parameters of the apparatuswhich affect a field pattern in the energy application zone. Theapparatus may comprise at least one processor configured to determine anamount of energy to be supplied to the at least one radiating element ateach of the plurality of MSEs. The processor may be further configuredto determine an energy application schedule, the energy applicationschedule comprising timing instructions for applying energy at at leasta subset of the plurality of MSEs; and cause application of energyaccording to the determined amounts of energy and the determined energyapplication schedule.

In some embodiments, the energy application schedule may includeinstructions to apply energy at an irregular order. Additionally, oralternatively, the energy application schedule may include instructionsto intermit energy application between two or more energy applicationevents.

In some embodiments, the processor may be configured to determine theschedule based on feedback received from the energy application zone.The feedback may include EM feedback. In some embodiments, the processormay be configured to group MSEs into MSE groups, and determine theenergy application schedule according to the grouping. In someembodiments, the processor may be further configured to group MSEs intoa first MSE group and a second MSE group, and the energy applicationschedule may further comprise applying no more than a first number ofMSEs from the first group before applying MSEs from the second group. Insome embodiments, the first number may be one.

In some embodiments, the processor may be configured to group the MSEsinto MSE groups based on EM feedback received from the energyapplication zone. The processor may be further configured to determinethe energy application schedule according to the MSE groups.Additionally, or alternatively, the processor may be configured to groupMSEs into groups according to values of one or more modulation spacevariables. Additionally, or alternatively, the processor may beconfigured to group MSEs into groups according to frequency values ofthe MSEs. In some embodiments, the energy application schedule mayinclude one or more intermissions between subsequent energy applicationevents, each of the intermissions being shorter by at least 90% from atime duration, at which heat diffuses 1 cm in the object. In someembodiments, the energy application schedule may include instructions tointermit energy application between two or more energy applicationevents for a period of 1 second or less. In some embodiments, one ormore of the intermissions may be shorter than a typical energyapplication event.

In some embodiments, the apparatus may further include an interfaceconfigured to receive data. In some such embodiments the processor maybe further configured to determine the energy application schedule basedon the data. In some embodiments, the interface may be configured toreceive the data from outside the energy application zone. In someembodiments, the interface may include a user interface. In someembodiments, the interface may include a connection to a communicationnetwork, for example, an Internet connection. In some embodiments, theinterface may include a reader for a machine readable element. Forexample, the machine readable element may include a barcode and/or anRFID tag.

Exemplary aspects of the invention may be directed towards a method ofapplying EM energy to an object in an energy application zone via atleast one radiating element at a plurality of MSEs. The method maycomprise determining an amount of EM energy to be supplied to theradiating elements at the plurality of MSEs, determining an energyapplication schedule comprising timing instructions for applying energyat at least a subset of the plurality of MSEs. The method may furthercomprise causing application of EM energy according to the determinedamounts of energy and the determined energy application schedule.

The energy application schedule may further comprise instructions toapply the EM energy at an irregular order. The energy applicationschedule may further comprise instructions to intermit energyapplication between two or more energy application events. The methodmay further comprise determining the energy application schedule basedon feedback received from the energy application zone. The feedback mayfurther comprise EM feedback. The method may further comprise groupingMSEs into MSE groups and determining the energy application scheduleaccording to the MSE groups. The method may further comprise groupingMSEs into a first MSE group and a second MSE group, and wherein theenergy application schedule may further comprise applying no more than afirst number of MSEs from the first group before applying MSEs from thesecond group. Optionally, the first number of MSEs may be one. Themethod may further comprise grouping MSEs into MSE groups based on EMfeedback received from the energy application zone and determining theenergy application schedule according to the MSE groups. The grouping ofMSEs into groups may be based on values of one or more modulation spacevariables. The grouping of MSEs into groups may be based on frequencyvalues of the MSEs.

The energy application schedule may further comprise one or moreintermissions between energy application events, at least one of the oneor more intermissions being shorter by at least 90% from a time durationat which heat diffuses 1 cm in the object. The energy applicationschedule may further include instructions to intermit energy applicationbetween two or more energy application events for a period of 1 secondor less.

An average duration of an intermission may be smaller than an averageduration of an energy application event. The method may further comprisereceiving data via an interface and determining the energy applicationschedule based on the received data. In some embodiments, the interfacemay be configured to receive the data from outside the energyapplication zone. The interface may comprise a user interface. Theinterface may comprise a connection to a communication network. Theinterface may comprise an Internet connection. The interface maycomprise a reader for a machine readable element. The machine readableelement may comprise a barcode or an RFID tag.

Exemplary aspects of the invention may be directed towards a method forapplying EM energy to an object at a plurality of MSEs. The method maycomprise: (a) grouping a number of the plurality of MSEs into at least afirst subset and a second subset according to a first grouping rule, (b)associating a first EM energy application protocol with the first subsetand a second EM energy application protocol with the second subset, (c)applying energy at each MSE according to the first and second EM energyapplication protocols, (d) grouping the number of the plurality of MSEsinto a third subset and a fourth subset according to a second groupingrule, and (e) associating a third EM energy application protocol withthe third subset and a fourth EM energy application protocol with thefourth subset, and (f) applying the EM energy at each of the pluralityof MSEs according to the third and fourth EM energy applicationprotocols. In some embodiments, the method may include associating eachMSE with a value of an absorbability indicator. In some embodiment, theat least one of the grouping rules may dictate grouping according tovalues of the absorbability indicator. In some embodiments, the methodmay include associating each MSE with a value of an absorbabilityindicator. In some embodiments, the grouping rules may include thresholdvalues and dictate grouping according to the values of the absorbabilityindicator in reference to the threshold values. In some embodiments, therules may differ from one another in the threshold values.

Exemplary aspects of the invention may be directed towards an apparatusfor applying EM energy to a load at a plurality of MSEs. The apparatusmay comprise at least one processor configured to: (a) group a number ofthe plurality of MSEs into at least a first subset and a second subsetaccording to a first grouping rule, (b) associate a first EM energyapplication protocol with the first subset and a second EM energyapplication protocol with the second subset, (c) cause application ofenergy at each MSE according to first and second EM energy applicationprotocol, (d) group the number of the plurality of MSEs into a thirdsubset and a fourth subset according to a second grouping rule, and (e)associate a third EM energy application protocol with the third subsetand a fourth EM energy application protocol with the fourth subset, and(f) apply the EM energy at each of the plurality of MSEs according tothe third and fourth EM energy application protocols.

In some embodiments, the at least one processor may be furtherconfigured to associate each MSE with a value of an absorbabilityindicator. In some embodiments, at least one of the grouping rulesdictates grouping according to values of the absorbability indicator. Insome embodiments, the at least one processor may be further configuredto associate each MSE with a value of an absorbability indicator. Insome embodiments, the grouping rules include threshold values anddictate grouping according to the values of the absorbability indicatorin reference to the threshold values. In some embodiments, the first andsecond threshold values may be different.

The drawings and detailed description which follow contain numerousalternative examples consistent with the invention. A summary of everyfeature disclosed is beyond the object of this summary section. For amore detailed description of exemplary aspects of the invention,reference should be made to the drawings, detailed description, andclaims, which are incorporated into this summary by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic representation of an apparatus for applying EMenergy to an object, in accordance with some exemplary embodiments ofthe present invention;

FIG. 2A is a view of a cavity, in accordance with some exemplaryembodiments of the present invention;

FIG. 2B is a view of a cavity, in accordance with some exemplaryembodiments of the present invention;

FIG. 3A is a diagrammatic representation of an apparatus for applying EMenergy to an object, in accordance with some exemplary embodiments ofthe present invention;

FIG. 3B is a diagrammatic representation of an apparatus for applying EMenergy to an object, in accordance with some exemplary embodiments ofthe present invention;

FIG. 4 is a flow chart of a method for applying EM energy to an energyapplication zone in accordance with some embodiments of the presentinvention;

FIG. 5 is a graphical presentation of AI measurement results obtainedfrom a pizza;

FIG. 6 is a flowchart of a method for applying RF energy according tosome embodiments of the invention.

FIG. 7A-7C include graphs illustrating formulas for determining amountsof energy based on values of a parameter, in accordance with someembodiments of the invention;

FIG. 8 is a graphical presentation of an exemplary grouping rule, forgrouping MSEs; and

FIG. 9 is a graphical representation of the amounts of energy that maybe applied to different MSEs using the rule depicted in FIG. 8 and theenergy application protocols depicted in FIGS. 7A and 7C.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. When appropriate, the same reference numbers are usedthroughout the drawings to refer to the same or like parts.

In one respect, the invention may involve apparatus and methods forapplying EM energy. The term EM energy, as used herein, includes energydeliverable by EM radiation in all or portions of the EM spectrum,including but not limited to, radio frequency (RF), infrared (IR), nearinfrared, visible light, ultraviolet, etc. In one particular example,applied EM energy may include RF energy with a wavelength in free spaceof 100 km to 1 mm, which corresponds to a frequency of 3 KHz to 300 GHz,respectively. In some other examples, the applied EM energy may fallwithin frequency bands between 500 MHz to 1500 MHz or between 700 MHz to1200 MHz or between 800 MHz-1 GHz. Applying energy in the RF portion ofthe EM spectrum is referred herein as applying RF energy. Microwave andultra high frequency (UHF) energy, for example, are both within the RFrange. In some other examples, the applied EM energy may fall onlywithin one or more ISM frequency bands, for example, between 433.05 and434.79 MHz, between 902 and 928 MHz, between 2400 and 2500 MHz, and/orbetween 5725 and 5875 MHz. Even though examples of the invention aredescribed herein in connection with the application of RF energy, thesedescriptions are provided to illustrate a few exemplary principles ofthe invention, and are not intended to limit the invention to anyparticular portion of the EM spectrum.

In certain embodiments, the application of EM energy may occur in an“energy application zone”, such as energy application zone 9, as shownin FIG. 1. Energy application zone 9 may include any void, location,region, or area where EM energy may be applied. It may be hollow, or maybe filled or partially filled with liquids, solids, gases, orcombinations thereof. By way of example only, energy application zone 9may include an interior of an enclosure, interior of a partialenclosure, open space, solid, or partial solid, that allows existence,propagation, and/or resonance of EM waves. Zone 9 may include a conveyorbelt or a rotating plate. For purposes of this disclosure, all suchenergy application zones may alternatively be referred to as cavities.It is to be understood that an object is considered “in” the energyapplication zone if at least a portion of the object is located in thezone or if some portion of the object receives delivered EM radiation.

Application of EM energy may result in excitation of an EM field ofparticular pattern in the energy application zone. The field pattern maybe determined, or at least influenced by one or more parameters.

The term “modulation space” or “MS” is used to collectively refer to allthe parameters that may affect a field pattern in the energy applicationzone and all combinations thereof. In some embodiments, the “MS” mayinclude all possible components that may be used and their potentialsettings (absolute and/or relative to others) and adjustable parametersassociated with the components. For example, the “MS” may include aplurality of variable parameters, the number of antennas, theirpositioning and/or orientation (if modifiable), the useable bandwidth, aset of all useable frequencies and any combinations thereof, powersettings, phases, etc. The MS may have any number of possible variableparameters, ranging between one parameter only (e.g., a one dimensionalMS limited to frequency only or phase only—or other single parameter),two or more dimensions (e.g., varying frequency and amplitude or varyingfrequency and phase together within the same MS), or many more.

Each variable parameter associated with the MS is referred to as an MSdimension. By way of example, a three dimensional modulation space hasthree dimensions, for example frequency (F), phase (P), and amplitude(A). In such three dimensional MS, frequency, phase, and amplitude(e.g., an amplitude difference between two or more waves beingtransmitted at the same time) of the EM waves are modulated duringenergy supply, while all the other parameters may be fixed during energysupply. The MS may have any number of dimensions, e.g., one dimension,two dimensions, four dimensions, n dimensions, etc. In one example, aone dimensional modulation space oven may provide MSEs that differ onefrom the other only by frequency,

The term “modulation space element” or “MSE,” may refer to a specificset of values of the variable parameters in MS. Therefore, the MS mayalso be considered to be a collection of all possible MSEs. For example,two MSEs may differ one from another in the relative amplitudes of theenergy being supplied to a plurality of radiating elements. For example,a three-dimensional MSE may include a specific frequency F(i), aspecific phase P(i), and a specific amplitude A(i). If even one of theseMSE variables changes, then the new set defines another MSE. Forexample, (3 GHz, 30°, 12 V) and (3 GHz, 60°, 12 V) are two differentMSEs, although they differ only in the phase component.

Differing combinations of these MS parameters may lead to differingfield patterns across the energy application zone and differing energydistribution patterns in the object. A plurality of MSEs that can beexecuted sequentially or simultaneously to excite a particular fieldpattern in the energy application zone may be collectively referred toas an “energy application scheme.” For example, an energy applicationscheme may consist of three MSEs: (F(1), P(1), A(1)); (F(2), P(2),A(2)); (F(3), P(3), A(3)). Such an energy application scheme may resultin applying the first, second, and third MSE to the energy applicationzone.

The invention, in its broadest sense, is not limited to any particularnumber of MSEs or MSE combinations. Various MSE combinations may be useddepending on the requirements of a particular application and/or on adesired energy transfer profile, and/or given equipment, e.g., cavitydimensions. The number of options that may be employed could be as fewas two or as many as the designer desires, depending on factors such asintended use, level of desired control, hardware or software resolutionand cost.

In accordance with some embodiments of the invention, an apparatus ormethod may involve the use of at least one source configured to apply EMenergy to the energy application zone. A “source” may include anycomponent(s) that are suitable for generating and supplying EM energy,for example, an RF power source(s), amplifier(s) (e.g., solid stateamplifier), waveguide(s), radiating element(s), etc.

Consistent with some embodiments of the invention, EM energy may beapplied to the energy application zone in the form of propagating EMwaves at selected wavelengths or frequencies (also known as EMradiation). As used consistently herein, “propagating EM waves” mayinclude resonating waves, evanescent waves, and waves that travelthrough a medium in any other manner. EM radiation carries energy thatmay be imparted to (or dissipated into) matter with which it interacts.

As used herein, if a machine (e.g., a processor) is described as“configured to” perform a task (e.g., configured to cause application ofa selected field pattern), then, at least in some embodiments, themachine may include components, parts, or aspects (e.g., software) thatenable the machine to perform the task. In some embodiments, the machinemay also perform this task during operation. Similarly, when a task isdescribed as being done “in order to” establish a target result (e.g.,in order to apply a plurality of EM field patterns to the object), then,at least in some embodiments, carrying out the task would accomplish thetarget result wholly or partially.

In certain embodiments, EM energy may be applied to an object 11. Anyreference to an “object” (or “object to be heated” or “object to beprocessed”) to which EM energy is applied is not limited to a particularform. An object may include a liquid, semi-liquid, solid, semi-solid, orgas, depending upon the particular process with which the invention isutilized. The object may also include composites or mixtures of matterin differing phases. Thus, by way of non-limiting example, the term“object” encompasses such matter as food to be defrosted or cooked;clothes or other wet material to be dried; frozen organs to be thawed;chemicals to be reacted; fuel or other combustible material to becombusted; hydrated material to be dehydrated, gases to be expanded;liquids to be heated, boiled or vaporized, or any other material forwhich there is a desire to apply, even nominally, EM energy.

In some embodiments, a portion of EM energy applied to energyapplication zone 9 (e.g., via the radiating elements) may be absorbed byobject 11. In some embodiments, another portion of the EM energy appliedor delivered to energy application zone 9 may be absorbed by variouselements (e.g., food residue, particle residue, additional objects,structures associated with zone 9, or any other EM enemy-absorbingmaterials found in zone 9) associated with energy application zone 9.Energy application zone 9 may also include loss constituents that donot, themselves, absorb an appreciable amount of EM energy, butotherwise account for EM energy losses. Such loss constitutes mayinclude, for example, cracks, seams, joints, doors, an interface betweena door and a cavity or any other loss mechanisms associated with energyapplication zone 9. Thus, in some embodiments, a load may include atleast a portion of object 11 along with any EM energy-absorbingconstituents in the energy application zone as well as any EM energyloss constituents associated with the zone.

FIG. 1 is a diagrammatic representation of an apparatus 100 for applyingEM energy to an object, in accordance with some embodiments of theinvention. Apparatus 100 may include a controller 101, an array 102 a ofradiating elements 102 (e.g., antennas) including one or more radiatingelements, and energy application zone 9. Controller 101 may beelectrically coupled to one or more radiating elements 102. As usedherein, the term “electrically coupled” refers to one or more eitherdirect or indirect electrical connections. Controller 101 may include acomputing subsystem 92, an interface 130, and an EM energy applicationsubsystem 96. Based on an output of computing subsystem 92, energyapplication subsystem 96 may respond by generating one or more radiofrequency signals to be supplied to radiating elements 102. In turn, theone or more radiating elements 102 may radiate EM energy into energyapplication zone 9. In certain embodiments, this energy may interactwith object 11 positioned within energy application zone 9.

Consistent with the presently disclosed embodiments, computing subsystem92 may include a general purpose or special purpose computer. Computingsubsystem 92 may be configured to generate control signals forcontrolling EM energy application subsystem 96 via interface 130.Computing subsystem 92 may further receive measured signals from EMenergy application subsystem 96 via interface 130.

While controller 101 is illustrated for exemplary purposes as havingthree subcomponents, control functions may be consolidated in fewercomponents, or additional components may be included consistent with thedesired function and/or design of a particular embodiment. Forexample—EM energy application subsystem 96 may not be part of controller101.

Exemplary energy application zone 9 may include locations where energyis applied—it may make part of an oven, chamber, tank, dryer, thawer,dehydrator, reactor, engine, chemical or biological processingapparatus, furnace, incinerator, material shaping or forming apparatus,conveyor, combustion zone, cooler, freezer, etc. In some embodiments,the energy application zone may be part of a vending machine, in whichobjects are processed once purchased. Thus, consistent with thepresently disclosed embodiments, energy application zone 9 may includean EM resonator 10 (also known as cavity resonator, or cavity)(illustrated for example in FIG. 2A). At times, energy application zone9 may be congruent with the object or a portion of the object (e.g., theobject or a portion thereof, is or may define the energy applicationzone).

FIG. 2A shows a sectional view of a cavity 10, which is one exemplaryembodiment of energy application zone 9. Cavity 10 may be cylindrical inshape (or any other suitable shape, such as semi-cylindrical,rectangular, elliptical, cuboid, symmetrical, asymmetrical, irregular,and regular, among others) and may be made of a conductor, such asaluminum, stainless steel or any suitable metal or other conductivematerial. In some embodiments, cavity 10 may include walls coated and/orcovered with a protective coating, for example, made from materialstransparent to EM energy, e.g., metallic oxides or others. In someembodiments, cavity 10 may have a spherical shape or hemispherical shape(for example as illustrated in FIG. 2A). Cavity 10 may be resonant in aselected range of frequencies (e.g., within the UHF or microwave rangeof frequencies, such as between 300 MHz and 3 GHz, or between 400 MHzand 1 GHZ). It is also contemplated that cavity 10 may be closed, e.g.,completely enclosed (e.g., by conductor materials), bounded at leastpartially, or open, e.g., having non-bounded openings. The generalmethodology of the invention is not limited to any particular cavityshape or configuration, as discussed earlier. FIG. 2A shows a sensor 20and antennas 16 and 18 (examples of radiating elements 102 shown in FIG.1).

FIG. 2B shows a top sectional view of a cavity 200 according to anotherexemplary embodiment of energy application zone 9. FIG. 2B showsantennas 210 and 220 (as examples of radiating elements 102 shown inFIG. 1). Cavity 200 comprises a space 230 for receiving object 11 (notshown). Space 230, as shown between the dotted lines in FIG. 2B, has anessentially rectangular cross section, which may be adapted forreceiving a tray on top of which object 11 may be placed.

In some embodiments, field adjusting element(s) (not illustrated) may beprovided in energy application zone 9, for example, in cavity 10 and/orcavity 200. Field adjusting element(s) may be adjusted to change the EMwave pattern in the cavity in a way that selectively directs the EMenergy from one or more of antennas 16 and 18 (or 210 and 220) intoobject 11. Additionally or alternatively, field adjusting element(s) maybe further adjusted to simultaneously match at least one of the antennasthat act as transmitters, and thus reduce coupling to the other antennasthat act as receivers. An antenna that acts as a receiver may also beconsidered as a sensor.

Additionally, one or more sensor(s) (or detector(s)) 20 may be used tosense (or detect) information (e.g., signals) relating to object 11and/or to the energy application process and/or the energy applicationzone. For example—sensors (20) may send a feedback signal to controller101 (e.g., to computing subsystem 92). At times, one or more antennas,e.g., antenna 16, 18, 210 or 220, may be used as sensors. The sensorsmay be used to sense any information, including EM power, temperature,weight, humidity, motion, etc. The sensed information may be used forany purpose, including process verification, automation, authentication,safety, etc.

Automation may be affected, for example, by adjusting RF parameters,such as energy application time, power level, emitted frequency, phase,etc., in accordance with a feedback on the processed object received bythe sensor(s). For example, stopping or adjusting the processing, e.g.,heating, once the sensor(s) indicate that certain stopping or adjustingcriteria are met, for example, once sufficient amount of energy isabsorbed in the object, once one or more portions of the object are at aselected temperature, once time derivatives of absorbed power changes.Such automatic processing adjustment or stoppage may be useful, forinstance, in vending machines, where food products are kept cooled or atroom temperature, and heated or cooked only when purchased. Purchase maystart the heating, and specific heating conditions (for example, energysupplied at each MSE) are determined in accordance with feedback fromthe heated product. Additionally or alternatively, heating is stoppedonce the sensors sense conditions that are defined to the controller asstopping criteria. Additionally or alternatively, cooking or processinginstructions may be provided on a machine readable element, e.g.,barcode or a tag, associated with the processed object (e.g., heatedfood product, purchased in the vending machine).

In the presently disclosed embodiments, more than one feed and/or aplurality of radiating elements (e.g., antennas) may be provided. Theradiating elements may be adjacent to one or more walls of cavity 10, orotherwise located on one or more surfaces of, e.g., an enclosuredefining the energy application zone). Alternatively, radiating elementsmay be located inside or outside the energy application zone One or moreof the radiating elements may be near to, in contact with, in thevicinity of or even embedded in object 11 (e.g., when the object is aliquid). The orientation and/or configuration of each radiating elementmay be distinct or the same, based on the specific energy application,e.g., based on a desired target effect. Each radiating element may bepositioned, adjusted, and/or oriented to transfer EM waves along a samedirection, or various different directions. Furthermore, the location,orientation, and configuration of each radiating element may be selectedbefore applying energy to the object. Alternatively or additionally, thelocation, orientation, and configuration of each radiating element maybe dynamically adjusted, for example, by using a processor, duringoperation of the apparatus and/or between rounds of energy application.The invention is not limited to radiating elements having particularstructures or locations within the apparatus.

As represented by the block diagram of FIG. 1, apparatus 100 may includeat least one radiating element 102 in the form of at least one antennafor applying of EM energy to energy application zone 9. One or more ofthe radiating elements (e.g., antenna(s)) may also be configured toreceive EM energy from energy application zone 9. In other words,radiating element, as used herein may function as a transmitter, areceiver, or both, depending on a particular application andconfiguration. When a radiating element acts as a receiver of EM energyfrom an energy application zone (e.g., reflected EM waves), theradiating element receives EM energy from the energy application zone.

As used herein, the terms “radiating element” and “antenna” may broadlyrefer to any structure from which EM energy may radiate and/or bereceived. For example, a radiating element or an antenna may include anaperture/slot antenna, or an antenna which includes a plurality ofterminals transmitting in unison, either at the same time or at acontrolled dynamic phase difference (e.g., a phased array antenna).Consistent with some exemplary embodiments, radiating elements 102 mayinclude an EM energy transmitter (referred to herein as “a transmittingantenna” or “emitting radiating element”) that feeds energy into EMenergy application zone 9, an EM energy receiver (referred herein as “areceiving antenna”) that receives energy from zone 9, or a combinationof both a transmitter and a receiver. For example, a first antenna maybe configured to emit EM energy to zone 9, and a second antenna may beconfigured to receive energy from the first antenna. In someembodiments, one or more antennas may each serve as both receivers andtransmitters. In some embodiments, one or more antennas may serve a dualfunction while one or more other antennas may serve a single function.So, for example, a single antenna may be configured to both emit EMenergy to the zone 9 and to receive EM energy via the zone 9; a firstantenna may be configured to emit EM energy to the zone 9, and a secondantenna may be configured to receive EM energy via the zone 9; or aplurality of antennas could be used, where at least one of the pluralityof antennas may be configured to both emit EM energy to zone 9 and toreceive EM energy via zone 9. At times, in addition to or as analternative to emitting and/or receiving energy, an antenna may also beadjusted to affect the field pattern. For example, various properties ofthe antenna, such as position, location, orientation, etc., may beadjusted. Different antenna property settings may result in differing EMfield patterns within the energy application zone thereby affectingenergy absorption in the object. Therefore, antenna adjustments mayconstitute one or more variables that can be varied for energyapplication control.

Consistent with the presently disclosed embodiments, energy may besupplied to one or more transmitting antennas. Energy supplied to atransmitting antenna may result in energy emitted by the transmittingantenna (referred to herein as “incident energy”). The incident energymay be delivered to zone 9, and may be in an amount equal to an amountof energy supplied to the transmitting antenna(s) by a source. A portionof the incident energy may be dissipated in the object or absorbed bythe object (referred to herein as “dissipated energy” or “absorbedenergy”). Another portion may be reflected back to the transmittingantenna (referred to herein as “reflected energy”). Reflected energy mayinclude, for example, energy reflected back to the transmitting antennadue to mismatch caused by the object and/or the energy application zone,e.g., impedance mismatch. Reflected energy may also include energyretained by the port of the transmitting antenna (e.g., energy that isemitted by the antenna but does not flow into the zone). The rest of theincident energy, other than the reflected energy and dissipated energy,may be coupled to one or more receiving antennas other than thetransmitting antenna (referred to herein as “coupled energy.”).Therefore, the incident energy (“I”) supplied to the transmittingantenna may include all of the dissipated energy (“D”), reflected energy(“R”), and coupled energy (“C”), and may be expressed according to therelationship:I=D+T+R.

In accordance with certain aspects of the invention, the one or moretransmitting antennas may deliver EM energy into zone 9. Energydelivered by a transmitting antenna into the zone (referred to herein as“delivered energy” or (d)) may be the incident energy emitted by theantenna minus the reflected energy at the same antenna. That is, thedelivered energy may be the net energy that flows from the transmittingantenna to the zone, i.e., d=I−R. Alternatively, the delivered energymay also be represented as the sum of dissipated energy and transmittedenergy, i.e., d=D+C (where C=ΣCi).

In certain embodiments, the application of EM energy may occur via oneor more power feeds. A feed may include one or more waveguides and/orone or more radiating elements (e.g., antennas 102) for applying EMenergy to the zone. Such radiating elements may include, for example,patch antennas, fractal antennas, helix antennas, log-periodic antennas,spiral antennas, slot antennas, dipole antennas, loop antennas, slowwave antennas, leaky wave antennas or any other structures capable oftransmitting and/or receiving EM energy.

The invention is not limited to radiating elements having particularstructures or locations. Radiating elements, e.g., antenna 102, may bepolarized in differing directions in order to, for example, reducecoupling, enhance specific field pattern(s), increase the energydelivery efficiency and support and/or enable a specific algorithm(s).The foregoing are examples only, and polarization may be used for otherpurposes as well. In one example, three antennas may be placed parallelto orthogonal coordinates, however, it is contemplated that any suitablenumber of antennas (such as one, two, three, four, five, six, seven,eight, etc.) may be used. For example, a higher number of antennas mayadd flexibility in system design and improve control of energydistribution, e.g., greater uniformity and/or resolution of energyapplication in zone 9.

In certain embodiments, there may be provided at least one processor. Asused herein, the term “processor” may include an electric circuit thatperforms a logic operation on input or inputs. For example, such aprocessor may include one or more integrated circuits, microchips,microcontrollers, microprocessors, all or part of a central processingunit (CPU), graphics processing unit (GPU), digital signal processors(DSP), field-programmable gate array (FPGA) or other circuit suitablefor executing instructions or performing logic operations. The at leastone processor may be coincident with or may be part of controller 101.

The instructions executed by the processor may, for example, bepre-loaded into the processor or may be stored in a separate memory unitsuch as a RAM, a ROM, a hard disk, an optical disk, a magnetic medium, aflash memory, other permanent, fixed, or volatile memory, or any othermechanism capable of storing instructions for the processor. Theprocessor(s) may be customized for a particular use, or can beconfigured for general-purpose use and can perform different functionsby executing different software.

If more than one processor is employed, all may be of similarconstruction, or they may be of differing constructions electricallyconnected or disconnected from each other. They may be separate circuitsor integrated in a single circuit. When more than one processor is used,they may be configured to operate independently or collaboratively. Theymay be coupled electrically, magnetically, optically, acoustically,mechanically or by other means permitting them to interact.

The at least one processor may be configured to cause EM energy to beapplied to zone 9 via one or more antennas, for example across a seriesof MSEs, in order to apply EM energy at each such MSE to object 11. Forexample, the at least one processor may be configured to regulate one ormore components of controller 101 in order to cause the energy to beapplied.

In certain embodiments, the at least one processor may be configured todetermine a value indicative of energy absorbable by the object at eachof a plurality of MSEs. This may occur, for example, using one or morelookup tables, by pre-programming the processor or memory associatedwith the processor, and/or by testing an object in an energy applicationzone to determine its absorbable energy characteristics. One exemplaryway to conduct such a test is through a sweep.

As used herein, a sweep may include, for example, the transmission overtime of energy at more than one MSE. For example, a sweep may includethe sequential transmission of energy at multiple MSEs in one or morecontiguous MSE band; the sequential transmission of energy at multipleMSEs in more than one non-contiguous MSE band; the sequentialtransmission of energy at individual non-contiguous MSEs; and/or thetransmission of synthesized pulses having a desired MSE/power spectralcontent (e.g., a synthesized pulse in time). The MSE bands may becontiguous or non-contiguous. Thus, during an MSE sweeping process, theat least one processor may regulate the energy supplied to the at leastone antenna to sequentially deliver EM energy at various MSEs to zone 9,and to receive feedback which serves as an indicator of the energyabsorbable by object 11. While the invention is not limited to anyparticular measure of feedback indicative of energy absorbable in theobject, various exemplary indicative values are discussed below.

During the sweeping process, EM energy application subsystem 96 may beregulated to receive EM energy reflected and/or coupled at radiatingelements(s) (e.g., antenna(s)) 102, and to communicate the measuredenergy information (e.g., information pertaining to and/or related toand/or associated with the measured energy) back to computing subsystem92 via interface 130, as illustrated in FIG. 1. Computing subsystem 92may then be regulated to determine a value indicative of energyabsorbable by object 11 at each of a plurality of MSEs based on thereceived information. Consistent with some of the presently disclosedembodiments, a value indicative of the absorbable energy may include adissipation ratio (referred to herein as “DR”) associated with each of aplurality of MSEs. As referred to herein, a “dissipation ratio” (or“absorption efficiency” or “power efficiency”), may be defined as aratio between EM energy absorbed by object 11 and EM energy suppliedinto EM energy application zone 9. In some embodiments, dissipationratio may be defined as a ratio between EM energy absorbed by object 11and EM energy delivered to zone 9. The delivered energy may be definedas the difference between the energy supplied to a radiating element andthe energy reflected back to the radiating element.

Energy that may be dissipated or absorbed by an object is referred toherein as “absorbable energy” or “absorbed energy”. Absorbable energymay be an indicator of the object's capacity to absorb energy or theability of the apparatus to cause energy to dissipate in a given object(for example—an indication of the upper limit thereof). In some of thepresently disclosed embodiments, absorbable energy may be calculated asa product of the incident energy (e.g., maximum incident energy)supplied to the at least one antenna and the dissipation ratio.Reflected energy (e.g., the energy not absorbed or transmitted) may, forexample, be a value indicative of energy absorbed by the object. By wayof another example, a processor might calculate or estimate absorbableenergy based on the portion of the incident energy that is reflected andthe portion that is coupled. That estimate or calculation may serve as avalue indicative of absorbed and/or absorbable energy.

During an MSE sweep, for example, the at least one processor may beconfigured to control a source of EM energy such that energy issequentially supplied to one or more radiating elements at a series ofMSEs. The at least one processor might then receive a signal indicativeof energy (or power) reflected at each MSE and, optionally, also asignal indicative of the energy (or power) coupled to other antennas ateach MSE. Using a known amount of incident energy supplied to theantenna and a known amount of energy reflected and/or coupled (e.g.,thereby indicating an amount of energy absorbed at each MSE), anabsorbable energy indicator may be calculated or estimated.Alternatively, the processor might simply rely on an indicator ofreflection and/or coupling as a value indicative of absorbable energy.

Absorbable energy may also include energy that may be dissipated by thestructures of the energy application zone in which the object is located(e.g., cavity walls) or leakage of energy at an interface between anoven cavity and an oven door. In some embodiments, the amount of EMenergy absorbed in the cavity walls may be substantially small, andthus, the amount of EM energy absorbed in the object may besubstantially equal to the amount of absorbable energy.

In some of the presently disclosed embodiments, a dissipation ratio maybe calculated using formula (1):DR=P _(abs) /P _(in)   (1)

Wherein P_(abs) is the power adsorbed in the object, and P_(in) is theincident power.

The dissipated (i.e. absorbed) power may be equated with the differencebetween the incident power and the power detected by sensors in oraround the cavity. If these sensors are only the radiating elements,equation (1) may be equivalent to equation (1a).DR=(P _(in) −P _(rf) −P _(cp))/P _(in)   (1a)

where P_(in) represents the EM energy and/or power supplied to antennas102, P_(rf) represents the EM energy and/or power reflected/returned atthe antenna that function as transmitter, and P_(cp) represents the EMenergy and/or power coupled at those antennas that function asreceivers. The nominator, (P_(in)−P_(rf)−P_(cp)) may be referred to as“non-detected power”, since this power is not detected to leave theenergy application zone, but is known to enter. Alternatively oradditionally, the nominator may be referred to as “absorbed power”,since it may provide a good estimation to the adsorbed power; andestimation that may be accurate if no power is lost by any mechanism(e.g., cavity walls) other than being absorbed by the object. The terms“non-detected energy” and “absorbed energy” may be similarly used torefer to the difference between incident energy on the one hand, and thesum of reflected and coupled energies on the other hand. DR may be aunit-less value between 0 and 1, and thus may be represented by apercentage number.

Alternatively or additionally, another kind of dissipation ratio may becalculated using formula (2a):Δρ=P _(abs)/(P _(in) −P _(rf))   (2a)

Replacing P_(abs) with (P_(in)−P_(rf)P_(cp)), as done above may resultin equation (2b) for Δρ:Δρ=(P _(in) −P _(rf) −P _(cp))/(P _(in) −P _(rf))   (2b)

This dissipation ratio may measure the amount of dissipated power (ornon-detected power) as a portion of the delivered power, that is, thepower that was emitted and did not return to the emitting radiatingelement. It is noted that the incident, reflected, and coupled powersmay also be indicative of the respective energies. This dissipationratio may be useful to identify frequencies at which the object absorbsa lot of the energy delivered to the energy application zone, even ifonly a small portion of the supplied energy is delivered to the zone,and a large portion is reflected back to or retained at the emittingradiating element, for example, due to poor matching. The use of Δρ maybe limited to apparatuses that provide energy via two or more radiatingelements, because if only one radiating element exists, no energy may becoupled from one radiating element to another, and Δρ may equal 1 bydefinition.

For example, consistent with an embodiment which is designed for threeantennas 1, 2, and 3, computing subsystem 92 may be configured todetermine input reflection coefficients S₁₁, S₂₂, and S₃₃ and thetransfer coefficients (which may also be referred to as transmissioncoefficients) may be S₁₂=S₂₁, S₁₃, S₂₃=S₃₂ based on a measured powerand/or energy information during the sweep. Accordingly, the dissipationratio DR corresponding to antenna 1 may be determined based on the abovementioned reflection and transmission coefficients, according to formula(3):DR ₁=1−(IS ₁₁ I ² +IS ₁₂ I ² +IS ₁₃ I ²).   (3)

Similarly, the dissipation ratio Δρ corresponding to antenna 1 may bedetermined based on the above mentioned reflection and transmissioncoefficients, according to formula (3a):Δρ1=[1−(IS ₁₁ I ² +IS ₁₂ I ² +IS ₁₃ I ²)]/(1−|S ₁₁|²)=DR1/(1−|S ₁₁|²)  (3a)

In some embodiments, a common DR may be defined for the two radiatingelements:DR ₁₊₂ =P _(abs)/(P _(in1) +P _(in2))DR ₁₊₂=[(P _(in1) +P _(in2))−(P _(out1) P _(out2))]/(P _(in1) +P _(in2))

wherein the P_(in1) and P_(in2) are the power (or energy) incident atradiating element 1 and 2, respectively.

The value indicative of the absorbable energy may further involve themaximum incident energy associated with a power amplifier (notillustrated) of subsystem 96 at the given MSE. As referred herein, a“maximum incident energy” may be defined as the maximal power that maybe provided to the antenna at a given MSE throughout a given period oftime. Thus, one alternative value indicative of absorbable energy may bethe product of the maximum incident energy and the dissipation ratio.These are just two examples of values that may be indicative ofabsorbable energy which could be used alone or together as part ofcontrol schemes implemented in controller 101. Alternative indicators ofabsorbable energy may be used, depending for example on the structureemployed and the application,

In certain embodiments, the at least one processor may also beconfigured to cause energy to be supplied to the at least one radiatingelement in at least a subset of a plurality of MSEs. Energy transmittedto the zone at each of the subset of MSEs may be a function of theabsorbable energy value at the corresponding MSE. For example, energytransmitted to the zone at MSE(i) may be a function of the absorbableenergy value at MSE(i). The energy supplied to at least one antenna 102at each of the subset of MSEs may be determined as a function of theabsorbable energy value at each MSE (e.g., as a function of adissipation ratio, maximum incident energy, a combination of thedissipation ratio and the maximum incident energy, or some otherindicator). In some embodiments, the subset of the plurality of MSEsand/or the energy emitted to the zone at each of the subset of MSEs maybe determined based on or in accordance with a result of absorbableenergy information (e.g., absorbable energy feedback) obtained during anMSE sweep (e.g., at the plurality of MSEs). That is, using theabsorbable energy information, the at least one processor may adjustenergy supplied at each MSE such that the energy at a particular MSE mayin some way be a function of an indicator of absorbable energy at thatMSE. The functional correlation may vary depending upon applicationand/or a desired target effect, e.g., a more uniform energy distributionprofile may be desired across object 11. The invention is not limited toany particular scheme, but rather may encompass any technique forcontrolling the energy supplied by taking into account an indication ofabsorbable energy.

In certain embodiments, the at least one processor may be configured tocause energy to be supplied to the at least one radiating element in atleast a subset of the plurality of MSEs, wherein energy applied to thezone at each of the subset of MSEs is inversely related to theabsorbable energy value at the corresponding MSE. Such an inverserelationship may involve a general trend—e.g., when an indicator ofabsorbable energy in a particular MSE subset (i.e., one or more MSEs)tends to be relatively high, the actual incident energy at that MSEsubset may be relatively low. When an indicator of absorbable energy ina particular MSE subset tends to be relatively low, the incident energymay be relatively high. This substantially inverse relationship may beeven more closely correlated. For example, the supplied energy may beset such that its product with the absorbability indicator (i.e., avalue indicative of the energy absorbable by object 11) is substantiallyconstant across the MSEs applied.

Some exemplary energy application schemes may lead to more spatiallyuniform energy absorption in the object. As used herein, “spatialuniformity” may refer to a condition where the absorbed energy acrossthe object or a portion (e.g., a selected portion) of the object that istargeted for energy application is substantially constant (for exampleper volume unit or per mass unit). In some embodiments, the energyabsorption is considered “substantially constant” if the variation ofthe dissipated energy at different locations of the object is lower thana threshold value. For instance, a deviation may be calculated based onthe distribution of the dissipated energy in the object, and theabsorbable energy is considered “substantially constant” if thedeviation between the dissipation values of different parts of theobject is less than 50%. Because in many cases spatially uniform energyabsorption may result in spatially uniform temperature increase,consistent with the presently disclosed embodiments, “spatialuniformity” may also refer to a condition where the temperature increaseacross the object or a portion of the object that is targeted for energyapplication is substantially constant. The temperature increase may bemeasured by a sensing device, for example a temperature sensor providedin zone 9. In some embodiments, spatial uniformity may be defined as acondition, where a given property of the object is uniform orsubstantially uniform after processing, e.g., after a heating process.Examples of such properties may include temperature, readiness degree(e.g., of food cooked in the oven), mean particle size (e.g., in asintering process), etc.

In order to achieve control over the energy absorption in an object or aportion of an object, controller 101 may be configured to holdsubstantially constant the time duration at which energy is supplied toradiating elements 102 at each MSE, while varying the amount of powersupplied at each MSE as a function of the absorbable energy value. Insome embodiments, controller 101 may be configured to cause the energyto be supplied to the antenna at a particular MSE or MSEs at a powerlevel substantially equal to a maximum power level of the device and/orthe amplifier at the respective MSE(s) or other constant power level(which may or may not equal for all the MSEs).

Alternatively or additionally, controller 101 may be configured to varythe period of time during which energy is applied at each MSE as afunction of the absorbable energy value. At times, both the duration andpower at which each MSE is applied are varied as a function of theabsorbable energy value. Varying the power and/or duration of energysupplied at each MSE may be used to cause substantially uniform energyabsorption in the object or to have a controlled spatial pattern ofenergy absorption, for example, based on feedback regarding thedissipation properties of the object at each transmitted MSE.

Consistent with some embodiments, controller 101 may be configured tocause the source (e.g., by controlling the amplifier) to supply noenergy at all at particular MSE(s). Similarly, if the absorbable energyvalue exceeds a selected threshold, controller 101 may be configured tocause the antenna to supply energy at a power level less than a maximumpower level of the antenna.

Because absorbable energy can change based on a host of factorsincluding object temperature, in some embodiments, it may be beneficialto regularly update (e.g., by measuring feedback signals and/orcalculations based on such measurements) absorbable energy values andadjust energy application based on the updated absorbable values. Theseupdates can occur multiple times a second, or can occur every fewseconds or longer, depending on the requirements of a particularapplication,

In accordance with an aspect of some embodiments of the invention, theat least one processor (e.g., controller 101 or processor 2030,discussed below) may be configured to determine a desired and/or targetenergy absorption level at each of a plurality of MSEs and adjust energysupplied to the antennas at each MSE in order to obtain the targetenergy absorption level at each MSE. For example, controller 101 may beconfigured to target a desired energy absorption level at each MSE inorder to achieve or approximate substantially uniform energy absorptionacross a range of MSEs.

Alternatively, controller 101 may be configured to provide a targetenergy absorption level at each of a plurality of object portions, whichcollectively may be referred to as an energy absorption profile acrossthe object. An absorption profile may include uniform energy absorptionin the object, non-uniform energy absorption in the object, differingenergy absorption values in differing portions of the object,substantially uniform absorption in one or more portions of the object,or any other desirable pattern of energy absorption in an object orportion(s) of an object.

Reference is now made to FIG. 3A, which provides a diagrammaticrepresentation of an exemplary apparatus 100 for applying EM energy toan object, in accordance with some embodiments of the present invention.In accordance with some embodiments, apparatus 100 may include aprocessor 2030 which may regulate modulations performed by modulator2014. In some embodiments, modulator 2014 may include at least one of aphase modulator, a frequency modulator, and an amplitude modulatorconfigured to modify the phase, frequency and amplitude of an ACwaveform generated by power supply 2012. Processor 2030 mayalternatively or additionally regulate at least one of location,orientation, and configuration of each radiating element 2018, forexample, using an electro-mechanical device. Such an electromechanicaldevice may include a motor or other movable structure for rotating,pivoting, shifting, sliding or otherwise changing the orientation and/orlocation of one or more of radiating elements 2018. Alternatively oradditionally, processor 2030 may be configured to regulate one or morefield adjusting elements located in the energy application zone, inorder to change the field pattern in the zone,

In some embodiments, apparatus 100 may involve the use of at least onesource configured to deliver EM energy to the energy application zone.By way of example, and as illustrated in FIG. 3A, the source may includeone or more of a power supply 2012 configured to generate EM waves thatcarry EM energy. For example, power supply 2012 may be a magnetronconfigured to generate high power microwave waves at a selectedwavelength or frequency. Alternatively, power supply 2012 may include asemiconductor oscillator, such as a voltage controlled oscillator,configured to generate AC waveforms (e.g., AC voltage or current) with aconstant or varying frequency and/or solid-state amplifier. AC waveformsmay include sinusoidal waves, square waves, pulsed waves, triangularwaves, or another type of waveforms with alternating polarities.Alternatively, a source of EM energy may include any other power supply,such as EM field generator, EM flux generator, or any mechanism forgenerating vibrating electrons.

In some embodiments, apparatus 100 may include a phase modulator (whichmay be included, for example, in modulator 2014) that may be controlledto perform a selected sequence of time delays on an AC waveform, suchthat the phase of the AC waveform is increased by a number of degrees(e.g., 10 degrees) for each of a series of time periods. In someembodiments, processor 2030 may dynamically and/or adaptively regulatemodulation based on feedback from the energy application zone. Forexample, processor 2030 may be configured to receive an analog ordigital feedback signal from detector 2040. This signal may constituteelectromagnetic feedback, indicating, for example, an amount of EMenergy received from cavity 10, and processor 2030 may dynamicallydetermine a time delay at the phase modulator for the next time periodbased on the received feedback signal. In some embodiments, detector2040 may be associated with a dual directional coupler to measure thereflected energy and/or coupled energy.

In some embodiments, apparatus 100 may include a frequency modulator(not illustrated). The frequency modulator may include a semiconductoroscillator configured to generate an AC waveform oscillating at aselected frequency. The selected frequency may be in association with aninput voltage, current, and/or other signal (e.g., analog or digitalsignals). For example, a voltage controlled oscillator may be configuredto generate waveforms at frequencies proportional to the input voltage.

Processor 2030 may be configured to regulate an oscillator (notillustrated) to sequentially generate AC waveforms oscillating atvarious frequencies within one or more selected frequency bands. In someembodiments, a selected frequency band may include a working frequencyband, and the processor may be configured to cause the supply of energyat frequencies within a sub-portion of the working frequency band. Aworking frequency band may be a collection of frequencies selectedbecause, in the aggregate, they achieve a desired goal, and there isdiminished need to use other frequencies in the band if that sub-portionachieves the goal. Once a working frequency band (or subset orsub-portion thereof) is identified, the processor may sequentially applypower at each frequency in the working frequency band (or subset orsub-portion thereof). This sequential process may be referred to as“frequency sweeping.” In some embodiments, based on the feedback signalprovided by detector 2040, processor 2030 may be configured to selectone or more frequencies from a frequency band, and regulate anoscillator to sequentially generate AC waveforms at these selectedfrequencies.

Alternatively or additionally, processor 2030 may be further configuredto regulate amplifier 2016 to adjust amounts of energy supplied toradiating elements 2018, based on the feedback signal. Consistent withsome embodiments, detector 2040 may detect an amount of energy reflectedfrom the energy application zone and/or energy coupled at a particularfrequency, and processor 2030 may be configured to cause the amount ofenergy supplied at that frequency to be low when the reflected energyand/or transmitted energy is low. Additionally or alternatively,processor 2030 may be configured to cause one or more antennas to supplyenergy at a particular frequency over a short duration when thereflected energy is low at that frequency.

In some embodiments, the apparatus may include more than one source ofEM energy. For example, more than one oscillator may be used forgenerating AC waveforms of differing frequencies. The separatelygenerated AC waveforms may be amplified by one or more amplifiers.Accordingly, at any given time, radiating elements 2018 may be caused tosimultaneously emit EM waves at, for example, at two differingfrequencies to cavity 10.

Processor 2030 may be configured to regulate the phase modulator inorder to after a phase difference between two EM waves supplied to theenergy application zone (e.g., regulate a phase difference between tworadiating elements). In some embodiments, the source of EM energy may beconfigured to supply EM energy in a plurality of phases, and theprocessor may be configured to cause the transmission of energy at asubset of the plurality of phases. By way of example, the phasemodulator may include a phase shifter. The phase shifter may beconfigured to cause a time delay in the AC waveform in a controllablemanner within cavity 10, delaying the phase of an AC waveform anywherefrom between 0-360 degrees.

In some embodiments, a splitter (not illustrated) may be provided inapparatus 100 to split an AC signal, for example generated by anoscillator, into two AC signals (e,g, split signals). Processor 2030 maybe configured to regulate the phase shifter to sequentially causevarious time delays such that the phase difference between two splitsignals may vary over time. This sequential process may be referred toas “phase sweeping.” Similar to the frequency sweeping described above,phase sweeping may involve a working subset of phases selected toachieve a desired energy application goal. In some embodiments, phasedifference between two signals may be obtained directly from the powersource—for example: the output frequency and the phase emitted from eachradiating element may be determined by the source (for example: by usingDirect Digital Synthesizer).

The processor may be configured to regulate an amplitude modulator inorder to alter an amplitude of at least one EM wave supplied to theenergy application zone. In some embodiments, the source of EM energymay be configured to supply EM energy in a plurality of amplitudes, andthe processor may be configured to cause the application of energy at asubset of the plurality of amplitudes. In some embodiments, theapparatus may be configured to supply EM energy through a plurality ofradiating elements, and the processor may be configured to supply energywith differing amplitudes simultaneously to at least two radiatingelements.

Although FIG. 3A and FIGS. 2A and 2B illustrate circuits including tworadiating elements (e.g., antennas 16, 18; 210, 220; or radiatingelements 2018), it should be noted that any number of radiating elementsmay be employed, and the circuit may select combinations of MSEs throughselective use of radiating elements. By way of example only, in anapparatus having three radiating elements A, B, and C, amplitudemodulation may be performed with radiating elements A and B, phasemodulation may be performed with radiating elements B and C, andfrequency modulation may be performed with radiating elements A and C.In some embodiments amplitude may be held constant and field changes maybe caused by switching between radiating elements and/or subsets ofradiating elements. Further, radiating elements may include a devicethat causes their location or orientation to change, thereby causingfield pattern changes. The combinations are virtually limitless, and theinvention is not limited to any particular combination, but ratherreflects the notion that field patterns may be altered by altering oneor more MSEs.

Some or all of the forgoing functions and control schemes, as well asadditional functions and control schemes, may be carried out, by way ofexample, using structures such as the EM energy application subsystemsschematically depicted in FIG. 1 or FIG. 3A.

To facilitate information transfer to and from processor 2030, someembodiments may include an interface 2032, as shown in FIG. 3B.Interface 2032 may provide a conduit for information transfer to andfrom processor 2030 and may include any circuitry, components, ordevices suitable for transferring signals between processor 2030 and oneor more information sources. In some embodiments, interface 2032 mayinclude a data bus for carrying signals to and from processor 2030.

The information sources in communication with processor 2030 viainterface 2032 may include any suitable devices for providing signals toprocessor 2030. In some embodiments, interface 2032 may be configured totransfer signals to or receive signals from a man-machine interface2034. The signals may carry data. Man-machine interface 2034 may includeany suitable type of input device for receiving input from a user ofapparatus 100. In some embodiments, man-machine interface 2034 mayinclude a graphical user interface (GUI). Alternatively, oradditionally, man-machine interface 2034 may include any combination ofa plurality of buttons, a touch screen, microphone, pointer device, etc.useful for inputting information. Through man-machine interface 2034, auser may input one or more values associated with object 11 or with adesired procedure for processing object 11. For example, usingman-machine interface 2034, the user may provide an energy applicationschedule and/or any input parameter values associated thereof, by whichenergy may be applied to energy application zone 9 and/or object 11.Interface 2032 may also be configured to transfer signals to or receivesignals from a network connection 2038. Network connection 2038 may beused to connect apparatus 100 with one or more sources of informationlocated external to apparatus 100. For example, network connection 2038may provide a communication path to one or more remotely locatedcomputers, to the Internet, to an externally located database, etc. Insome embodiments, network connection 2038 may enable one or moreremotely located users or devices to input parameter values, runprograms, select energy application schedules, and/or enter commands foroperation of apparatus 100. The connection between interface 2032 andnetwork connection 2038 may be established using any appropriatecommunication hardware and communication protocols. For example, in someembodiments, network connection 2038 may include a router and/or otherappropriate hardware, and interface 2032 and network connection 2038 maybe in communication across either a wired or wireless connection.

Interface 2032 may also be configured to communicate with one or moreinformation readers 2036, which, in turn, may be adapted to read orreceive information associated with a machine readable element. Forexample, in some embodiments, the machine readable element may includeone or more of an RFID tag, a barcode, optical images or indicia, and/orcombinations thereof. In certain embodiments, the machine readableelement may be attached, affixed, or otherwise associated with object 11or its packaging. The machine readable element may include encodedinformation relating to object 11 and/or relating to a procedure forprocessing object 11. For example, information stored on the machinereadable element may include, e.g., a material type indicator, a weightassociated with object 11, an energy application schedule related toobject 11 and/or any input parameter values associated thereof, a totalamount of energy to be absorbed in object 11, a total amount of energyto be supplied to the radiating element(s) and/or any desiredcharacteristic of object 11 to be achieved through processing with EMenergy. In some embodiments, a user may manually operate informationreader 2036 and scan a selected machine readable element correspondingto a desired procedure for processing object 11. Further still,processor 2030 may be configured to control information reader 2036 insuch a manner that an appropriate machine readable element isautomatically selected for reading based, for example, on user inputprovided through man machine interface 2034.

As indicated, processor 2030 may be configured to regulate the source ofEM energy in order to control how EM energy is applied to energyapplication zone 9, for example, using which energy application scheduleor power supply protocol.

FIG. 4 represents a method for applying EM energy to an object inaccordance with some embodiments of the present invention. EM energy maybe applied to an object, for example, through at least one processorimplementing a series of steps of method 500 of FIG. 4.

In certain embodiments, method 500 may involve controlling a source ofEM energy (step 510). By way of example only, in step 510, the at leastone processor may be configured to control EM energy applicationsubsystem 96 or power supply 2012.

The source may be controlled to supply EM energy at a plurality of MSEs(e.g., at a plurality of frequencies, phases, amplitudes etc.) to atleast one radiating element, as indicated in step 520. Alternatively oradditionally, the source may be controlled to supply the EM energy tothe at least one radiating element at a plurality of phases and/or at aplurality of other parameters that may change the field pattern excitedin the cavity, that are generally referred herein as modulation spaceelements (MSEs).

Various examples of MSE supply, including sweeping, may be implementedin step 520. Alternatively or additionally, other schemes forcontrolling the source may be implemented so long as that scheme resultsin the supply of energy at a plurality of MSEs (for example:sequentially or simultaneously). The at least one processor may regulatesubsystem 96 to supply energy at multiple MSEs to at least onetransmitting radiating element (e.g., antenna 102).

In certain embodiments, the method may further involve a step 530 ofcalculating or otherwise determining a value indicative of energyabsorbable by the object. The determining may be at each of theplurality of MSEs supplied in step 520. An absorbable energy value mayinclude any indicator—whether calculated, measured, derived, estimatedor selected—of an object's capacity to absorb energy. For example,computing subsystem 92 may be configured to determine an absorbableenergy value, such as a dissipation ratio associated with each MSE.Processor 2030 may determine a value indicative of energy absorbable bythe object (e.g., DR) based on feedback signals received from detector2040. The absorbable energy values may be determined during a scan stage(to be further used in a heating stage).

In certain embodiments, the method may also involve adjusting an amountof EM energy incident at each of the plurality of MSEs based on theabsorbable energy value at each MSE (step 540). For example, in step540, the processor may determine an amount of energy to be applied ateach MSE (e.g., during the heating stage), as a function of theabsorbable energy value associated with that MSE.

In some embodiments, a choice may be made not to use all possible MSEs.For example, a choice may be made not to use all possible frequencies ina working band, such that the emitted frequencies are limited to a subband of frequencies, for example, where the Q factor in that sub band issmaller or higher than a threshold. Such a sub band may be, for example50 MHz wide 100 MHz wide, 150 MHz wide, or even 200 MHz wide or more.

In some embodiments, the processor may determine a weight, e.g., powerlevel, used for supplying the determined amount of energy at each MSE,as a function of the absorbable energy value. For example, amplificationratio of amplifier 2016 may be changed inversely with the energyabsorption characteristic of object 11 at each MSE. In some embodiments,when the amplification ratio is changed (e.g. inversely with the energyabsorption characteristic), energy may be supplied for a constant amountof time at each MSE. Alternatively or additionally, the at least oneprocessor may determine varying durations at which the energy issupplied at each MSE. For example, the duration and power may vary fromone MSE to another, such that their product correlates (e.g., inversely)with the absorption characteristics of the object. In some embodiments,the controller may use the maximum available power at each MSE, whichmay vary between MSEs. In some embodiments, the controller may use thesame power level at each MSE. This variation may be taken into accountwhen determining the respective durations at which the energy issupplied at maximum power at each MSE. In some embodiments, the at leastone processor and/or controller (e.g., controller 101) may determineboth the power level and time duration for supplying the energy at eachMSE.

In certain embodiments, the method may also involve supplying EM energyat a plurality of MSEs to the radiating elements (step 550) (forexample, at the amounts of energy determined in step 540. Step 550 maybe referred to as the heating stage. Respective weights are optionallyassigned to each of the MSEs to be transmitted (step 540) for examplebased on the absorbable energy value (as discussed above). EM energy maybe applied to cavity 10 via radiating elements, e.g., antenna 102, 16,18 or 2018.

Energy application may be interrupted periodically (e.g., several timesa second) for a short time (e.g., only a few milliseconds or tens ofmilliseconds). Once energy application is interrupted, in step 560, itmay be determined if the energy transfer should be terminated. Energyapplication termination criteria may vary depending on application. Forexample, for a heating application, termination criteria may be based ontime, temperature, total energy absorbed, or any other indicator thatthe process at issue is compete. For example, heating may be terminatedwhen the temperature of object 11 rises to a selected temperaturethreshold. In another example, in thawing application, terminationcriteria may be any indication that the entire object is thawed.

If in step 560, it is determined that energy transfer should beterminated (step 560: yes), energy transfer may end in step 570. If thecriterion or criteria for termination is not met (step 560: no), it maybe determined if variables should be changed and reset in step 580. Ifnot (step 580: no), the process may return to step 550 to continuetransmission of EM energy. Otherwise (step 580: yes), the process mayreturn to step 520 to determine new variables. For example, after a timehas lapsed, the object properties may have changed; which may or may notbe related to the EM energy transmission. Such changes may includetemperature change, translation of the object (e.g., if placed on amoving conveyor belt or on a rotating plate), change in shape (e.g.,mixing, melting or deformation for any reason) or volume change (e.g.,shrinkage or puffing) or water content change (e.g., drying), flow rate,change in phase of matter, chemical modification, etc. Therefore, attimes and in response, it may be desirable to change the variables oftransmission. The new variables that may be determined may include: anew set of MSEs (e.g., frequencies), an amount of EM energy incident ordelivered at each of the plurality of MSEs, weight, e.g., power level,of the MSE(s) and duration at which the energy is supplied at each MSE.Consistent with some of the presently disclosed embodiments, less MSEsmay be swept in step 520 performed during the energy application phasethan those swept in step 520 performed before the energy applicationphase, such that the energy application process is interrupted for aminimum amount of time.

In some embodiments, steps 510-550 may be repeated plurality of timeswhile processing the object—for example: until a stop signal isreceived, e.g., from a user interface.

An aspect of some embodiments of the invention may relate to determiningan energy application schedule, and applying RF energy according to thedetermined schedule.

An energy application schedule may include, for example, timinginstructions for applying energy at a plurality of energy applicationevents. Each energy application event may include energy application ata single MSE. In some embodiments, an energy application event may alsoinclude intermissions in energy application, for example, when an energyapplication event includes energy application in a duty cycle of lessthan 100%, for instance, when an energy application event includespulsed application of energy. In some embodiments, two or more energyapplication events, sequential or not, may include energy application atthe same MSE.

The timing included in an energy application schedule may be relative,for example, timing of one event with respect to another. For example,in some embodiments, the timing instructions may include an ordering ofenergy application events. Additionally, or alternatively, an energyapplication schedule may include intermissions or pauses between energyapplication events.

An energy application event may be characterized by and/or relate to anMSE. The MSE may include values of controllable variables that mayaffect field distribution excited in the energy application zone, forexample, which radiating elements are to be activated during the energyapplication event, at what frequency or frequencies, at what phasedifference between them, a position and/or orientation of each radiatingelement, position and/or orientation of other conductive elements thatmay be controlled to modify the field pattern in the energy applicationzone, current, voltage, or other electrical parameters that may beapplied to devices that might affect the field pattern in the energyapplication zone (e.g., current flowing in a coil adjacent a ferriteelement), or values of any other parameters, which together define amodulation space element in the apparatus.

An energy application event may also be characterized by and/orassociated with a power supply protocol. A power supply protocol mayinclude, for example, instruction as to how much power is to be suppliedto each of the radiating elements during the energy application eventand/or instructions as to how long should the energy application eventtake. In some embodiments, a power supply protocol may includeinstructions to vary amounts of power supplied to one or more of theradiating elements during the energy application event. Power supplyprotocols are discussed in more detail in U.S. Provisional PatentApplication No. 61/595,399 entitled “RF Heating at Selected Power SupplyProtocols,” filed Feb. 6, 2012, and in U.S. Nonprovisional PatentApplication entitled “RF Heating at Selected Power Supply Protocols,”filed Feb. 5, 2013, both of which are fully incorporated herein byreference.

An energy application schedule may also include intermissions betweenenergy application events. The intermissions may be periods at whichlittle or no energy is applied. The energy application schedule maydetermine the length of such intermissions, and between which energyapplication events the intermissions should appear.

Table 1, below, is an illustration of an exemplary energy applicationschedule. The left column includes serial numbers of the energyapplication events. According to the energy application scheduleexemplified in Table 1, energy may be applied first at event #1, then atevent #2, and so on. The middle column in Table 1 includes the MSEs, atwhich energy may be applied for each event. In the Table, the exemplaryMSEs are shown as one-dimensional, and include frequency only. However,this is merely exemplary and the MSEs may be multi dimensional. Thepower supply protocol characterizing each energy application event inthe energy application schedule illustrated in Table 1 may be a defaultprotocol, common to all energy application events, and therefore neednot be specified in the energy application schedule. In someembodiments, different power supply protocols may be selected fordifferent energy application events, and a tabloid representation of anenergy application schedule may include a column specifying the powersupply protocol selected for each event.

in the right column in Table 1, intermissions that may be applied aftereach energy application event are provided. For example, an intermissionof 5 milliseconds is indicated, by the schedule depicted in Table 1,between energy application events #1 and #2. A minimal intermissionand/or an intermission of zero time duration (e.g. between event 4 andevent 5 in Table 1) may mean that energy application may cease only fora duration in a transition between MSEs. As used herein “intermission”is meant to refer to a deliberate cessation of energy application and itis to be understood that there may be additional delays in energyapplication arising from causes other than deliberate cessation ofenergy application (e.g., delays due to transition from one MSE toanother, delays inherent in energy-application related hardware, energyapplication-related devices or other devices used in the application ofenergy). Energy application arranged in events with intermissions ofzero time duration between them may be referred to as “continuous energyapplication.” Energy application arranged in events in which sometransitions have intermissions of zero time duration between them andsome do not may be referred to as “nearly continuous energyapplication.” In general, the intermissions making part of energyapplication schedules may be added to such hardware-requiredintermissions.

TABLE 1 # MSE [MHz] Intermission [ms] 1 800.0 5 2 800.5 1 3 801.0 0.5 4801.5 0 5 802.0 0.1 6 802.5 0

The order of MSEs at which energy may be applied according to an energyapplication schedule may be regular or irregular along each dimension ofthe modulation space. Exemplary ways of classifying orders by regularityare discussed below. As will be apparent from the following discussion,the order depicted in Table 1 may be classified as regular,

An order of MSEs may be regular or irregular along any dimension in themodulation space. For example, MSEs that are elements of a modulationspace having two dimensions (e,g, frequency and phase) may be orderedregularly or irregularly along each dimension of the MS. For example,MSEs including frequency values and phase values may be orderedregularly or irregularly along the frequency dimension, along the phasedimension, or along both. A variable that is a dimension of themodulation space, (e.g., frequency) may be referred to herein as amodulation space variable, or, in short, MS variable.

Table 2 depicts an energy application schedule, wherein an order of MSEsis regular along one modulation space variable and irregular alonganother. For example, the MSE order depicted in Table 2 is irregularalong the frequency dimension and regular along the phase dimension.

Intermissions, although possibly included in the energy applicationschedule depicted in Table 2, are not shown, because they may be ignoredfor determination of regularity or irregularity of the order.

TABLE 2 # Frequency [MHz] Phase [degrees] 1 800 0 2 810 120 3 801 240 4811 0 5 802 120 6 812 240

in Table 2, the order of the phases may be described to include cyclesof increasing phase, each cycle including three phases: 0, 120, and 240degrees. The order of the frequencies in Table 2 may be described toinclude cycles of increasing frequency, each cycle including twofrequencies: in the first cycle: 800 and 810 MHz, in the second cycle801 and 811 MHz, and in the third cycle 802 and 812 MHz.

Generally, energy application in any order of frequencies may includeenergy application in cycles of increasing (or decreasing) frequencyvalues. The same is true for any other MS variable. A change of coursefrom increase to decrease may occur when going from one cycle toanother. For example, according to the energy application scheduleexemplified in Table 2, energy may be applied at cycles of twofrequencies and at cycles of three phases. A cycle may be characterizedby a single direction of change from the value of an MS variable in oneenergy application event to the value of the same MS variable in asucceeding energy application event: either increase or decrease. Twoenergy application events, in which a value of an MS variable does notchange, may be considered a single energy application event for purposesof determination of the regularity of energy application order alongthat MS variable. The application of this idea is discussed below in thecontext of Table 4.

A change from increase to decrease or from decrease to increase mayindicate the beginning of a new cycle. Such a change may be referred toherein as a change of course or course change. Course changes may beidentified in Table 2, for example, between the second and third energyapplication events along the frequency column, and between the third andfourth energy application events along the phase column.

For example, an order of frequency values may be considered regular ifthe number of cycles (Nc) is about equal to the ratio between the numberof energy application events (Nevents) and the number of differentfrequency values included in the energy application schedule (Nvalues).The same may be true for an order of phase values, or for an order ofany other MS variable. Thus, generally, in a regular order,Nc=Nevents/Nvalues.

For example, in the energy application schedule depicted in Table 2,along the phase column, Nc=2; Nvalues=3; and Nevents=6, and therefore,Nc=Nevents/Nvalues, which may be a criterion for classifying an order asregular.

An order may be considered irregular if, for given numbers of energyapplication events and MS variable values, the number of cycles (Nc) islarger than in a regular order. In other words, in an irregular order,the number of cycles is greater than the ratio between the number ofenergy application events and the number of different values, andNc>Nevents/Nvalues.

For example, in Table 2, along the frequency column, Nc=3; Nvalues=6;and Nevents=6. Since, in the energy application schedule depicted inTable 2, Nc>Nevents/Nvalues (because 3>6/6) the order of frequencies inthis schedule may be considered irregular. It is noted that for thepurpose of determining regularity of an order, each energy applicationevent may be associated with only one cycle.

The number of values in each cycle along a given MS variable need not bethe same for all the cycles. For example, Table 3 depicts an irregularenergy application schedule with cycles of differing lengths.

TABLE 3 # Frequency [MHz] 1 2400 2 2410 3 2400 4 2420 5 2430 6 2402 72412 8 2403 9 2404 10 2405 11 2406 12 2407

The energy application schedule depicted in Table 3 includes four energyapplication cycles, the first of which includes energy applicationevents 1 and 2; the second—events 3, 4, and 5; the third—events 6 and 7;and the fourth includes events 8, 9, 10, 11, and 12. Since Nc=4,Nevent=12, and Nvalues=11, and 4 is larger than 12/11, the orderdepicted in Table 3 is irregular.

As discussed above, the number of energy application cycles in anirregular energy application order may be larger than in a regularorder. For example the number of cycles may be 2Nevents/Nvalues,3Nevents/Nvalues, 10Nevents/Nvalues, or larger or intermediate number.The coefficient 2, 3, 10, etc. may be referred to as “hopping level,”denoted by H. For example, if energy is applied at 100 differentfrequencies, and a series of 1000 consecutive energy application eventsincludes more than 10 cycles (e.g., 15 cycles), the energy applicationorder may be considered irregular and the hopping level H=15.

The hopping level, denoted with H, may be defined by the equationH=Nc·Nvalue/Nevents. According to some embodiments of the invention, anenergy application schedule may include instructions to apply energy atan irregular order, having a hopping level larger than 1 (e.g., 1.5, 2,3, 10, etc.) For example, the hopping level in Table 3 is4.11/12=44/12=3.667.

Applying energy at an irregular order along an MS variable may includeapplying energy at first and second values of the MS variable, andsubsequently applying energy at a value higher than the first and lowerthan the second before applying energy again at one of the first andsecond values.

For example, applying energy at an irregular order of frequencies mayinclude applying energy at a first frequency, then applying energy at asecond frequency, higher than the first, and then applying energy at athird frequency, lower than the second but higher than the first, beforeapplying energy again at the first or at the second frequency. Thefirst, second, and/or third frequencies may be applied atnon-consecutive energy application events, for example, at events number10, 50, and 100.

In another example, applying energy at an irregular order of frequenciesmay include applying energy at a first frequency, then applying energyat a second frequency, lower than the first, and then applying energy ata third frequency, lower than the first but higher than the second.

Table 4 depicts an energy application schedule, wherein energy isapplied at MSEs as written in the usual course of English writing (i.e.,from left to right and from top to bottom). Thus, the phases are appliedin 5 cycles, each cycle written in one of the rows. Regularity along thephase dimension is easily verified, since H_(phase)=5·4/20=1.

For purpose of determining the regularity along the frequency dimensionof the MS, it may be useful to consider all the consecutive events atwhich the frequency remains unchanged as a single energy applicationevent. Thus, each raw in Table 4 depicts a single energy applicationevent and the schedule includes two frequency cycles: one depicted inthe first three rows, and one depicted in the last two rows. The hoppingvalue along the frequency dimension may be determined then to beH_(frequency)=2*5/4=2.5.

TABLE 4 (2400, 0°) (2400, 90°) (2400, 180°) (2400 270°) (2410, 0°)(2410, 90°) (2410, 180°) (2410 270°) (2420, 0°) (2420, 90°) (2420, 180°)(2420 270°) (2401, 0°) (2401, 90°) (2401, 180°) (2401 270°) (2411, 0°)(2411, 90°) (2411, 180°) (2411 270°)

Additionally or alternatively to determining the order of energyapplication events, an energy application schedule may includeintermissions between energy application events. An intermission may bea time period starting at the end of one energy application event andending at the beginning of a succeeding energy application event. Anintermission may be a period of no energy application.

Intermissions may be characterized by the time they start and/or bytheir duration. For example, in Table 1 above, the starting time of eachintermission may be defined as the ending time of the preceding energyapplication event, and the duration of each intermission is given in theright column.

In some embodiments, an energy application schedule may includeinstructions to intermit energy application at certain predeterminedtimes, for example, each 30 seconds from the commencement of energyapplication (whether these 30 seconds include intermissions or not). Asused herein, if an aspect of energy application is “predetermined,” itis at least one of selected, chosen or determined prior to energyapplication. The verb “intermit” is used herein in the sense of stoptemporarily, pause for a short period of time.

In some embodiments, an energy application schedule may includeinstructions to apply energy intermittently upon occurrence of apredetermined occasion.

In one example, a predetermined occasion, which may be followed by anenergy application intermission, may include a continuous or partiallycontinuous supply of a predetermined amount of RF energy to theradiating elements. Continuous supply may mean supply with nointermission. Examples of amounts of supplied EM energy may include, forexample, 0.5 kJ, 1 kJ, or any smaller, larger, or intermediate amount ofRF energy.

In some embodiments, the predetermined occasion may include continuousor partially continuous supply of a predetermined amount of energy at asingle MSE. In some embodiments, the predetermined occasion may includecontinuous supply of a predetermined amount of energy at a group ofMSEs. MSE grouping is discussed below.

In another example, the predetermined occasion may be a continuousabsorption of a predetermined amount of RF energy by the object.Continuous absorption may mean absorption of energy during two or moreenergy application events that are not separated by an intermission. Theamount of energy absorbed at an MSE may be estimated by multiplying theamount of energy supplied to the radiating elements by an absorbabilityindicator, which may be any value indicative of energy absorbable in theload.

In some embodiments, the predetermined occasion may include continuousabsorption of a predetermined amount of energy by the object at a singleMSE. In some embodiments, the predetermined occasion may includecontinuous absorption of a predetermined amount of energy at a group ofMSEs.

In some embodiments, an energy application schedule may dictate anenergy application intermission after energy is continuously applied formore than a predetermined period (e.g., 5 ms). In some embodiments, anenergy application schedule may dictate an energy applicationintermission after energy is continuously applied for more than apredetermined period at a single MSE or at a predetermined group ofMSEs.

In some embodiments, an energy application schedule may be based on MSEgrouping. For example, an intermission may be set when continuous energyapplication to MSEs belonging to a single group exceeds somepredetermined threshold. In another example, energy application ordermay be set such that the number, duration, or other characteristic ofconsecutive energy application events at the same group of MSEs is belowsome predetermined threshold.

In some embodiments, an energy application order may include energyapplication at an MSE of a first group, then at MSEs of one or moresecond groups, and only then at another MSE of the first group. In theseand other embodiments, there may be a maximum number of MSEs appliedfrom the first group before applying MSEs from the second (or othergroups). In some embodiments, the first number may be 10 or less, e.g.,5 or less, or 2. The maximum number may be one, in some embodiments. Insome embodiments, energy may be applied at one MSE from each of two ormore groups before returning to applying energy at another MSE of thefirst group. In some embodiments, the schedule may further determine anorder within a group. For example, in one group energy may be applied atMSEs of a first order (e.g., from lower to higher frequency), and inanother—in another order (for example, in an irregular order). In someembodiments, MSEs may be grouped to three or more groups.

In some embodiments, MSEs may be grouped together according to frequencyvalues, phase values, and/ or values of other MS variables. For example,one group may include all MSEs having frequency values of between 800MHz and 810 MHz, and another group may include all MSEs having frequencyvalues of between 810 MHz and 820 MHz. In another example, MSEs aregrouped such that all MSEs having the same phase value are groupedtogether. For example, one group may contain only MSEs having phasevalues of 30 degrees, another group may contain only MSEs having phasevalues of 120 degrees, etc. In some embodiments, MSEs may be groupedaccording to the values of two or more of the MS dimensions, forexample, one group may contain MSEs having frequency values in a firstfrequency range and phase values in a first phase-range, and anothergroup may contain MSEs having frequency values of the first frequencyrange, and phase values of a second phase range.

In some embodiments, MSEs may be grouped according to absorbabilityindicators (referred to herein as “AI”) associated with the variousMSEs. For example, the MSEs may be grouped according to values of AI,e.g., in a first group, MSEs having AI smaller than 0.2, in a secondgroup, MSEs having AI larger than 0.8, and all the other MSEs in a thirdgroup. In another example, MSEs may be grouped according to theirassociation with AI peaks. For example, FIG. 5 shows AI measurementresults obtained from a pizza heated by EM energy after 11 minutes ofheating (first five minutes for thawing, and the rest for cooking).Heating by EM energy included energy application at a plurality offrequencies at a bandwidth of 800-1000 MHz. Based on these measurementresults, frequencies may be grouped according to AI peaks they may beassociated with (e.g., such that each group includes at least one peak).For example, in the case shown in FIG. 5, a first group may include thefrequencies between 800 and 875 MHz, a second group may include thefrequencies between 875 and 940 MHz, the third group may includefrequencies between 940 and 960 MHz, the fourth may include frequenciesbetween 960 and 980 MHz, and the fifth and last group may includefrequencies between 980 and 1000 MHz, all as depicted by the thickvertical lines in FIG. 5. In some embodiments, the frequency rangebetween 800 and 960 MHz may be divided into two groups, separatingbetween the two peaks included in this frequency range, for example.Since peaks may change during RF application process, so may thegrouping. Changing the grouping, or, more generally, the energyapplication schedule, may happen also under other circumstances. Forexample, the schedule may be changed by a user, and/or the processor maydetermine differing schedules during differing sweeps, and in othercases.

In some embodiments, an energy application schedule may include aduration of one or more of the intermissions. For example, an energyapplication schedule may include intermissions, ail having the same timeduration. In another example, the energy application schedule mayinclude intermissions of different time durations.

In some embodiments, a portion of the intermissions (e.g., 10%, 50%, orall of the intermissions) may be shorter than 1 second, optionally,shorter than 0.1 seconds.

In some embodiments, a portion of the intermissions may be proportionalto the time duration of a typical energy application event. Theproportion coefficient may be, for example, 0.1, 10, or any intermediatevalue. In some embodiments, the time duration of an energy applicationevent may be the average, median, or mode, of time durations of theenergy application events in an energy application schedule.

In some embodiments, an intermission may be a fraction, for example 10%or less of a time it takes heat to diffuse 1 cm in the object. Forexample, heat diffusion in metal is generally of about 1 cm per minute,and an intermission between energy application events at twosequentially applied MSEs may be 6 seconds or less (e.g., one second orless, a 1/10 of a second, a 1/100 of a second, or intermediatedurations, for example, 5/100 of a second). Without being bound bytheory, it is suggested that such short intermissions may allow heat todiffuse from hot centers, where RF energy tends to concentrate, to lesshot nearby surroundings, and therefore may reduce thermal runaways. Athermal runaway may occur when a hot center changes its dielectricproperties such that more and more of the RF energy concentrates at thecenter. It is suggested that short intermissions in energy applicationmay allow the hot centers to change their dielectric properties moremoderately or slowly, and this way limit thermal runaways. Thus, even ifheat does not diffuse a considerable distance during the intermission(e.g., in comparison to a wavelength of the RF), the intermission mayhelp in reducing thermal runaways and increasing heating uniformity.

In some embodiments, some energy application schedules may be availableto the processor, and the processor may select between them. Selectionmay be, for example, based on user instructions; provided via a userinterface, for example, from a machine readable element, which may beassociated with the object or a portion thereof; or may be determinedbased on feedback from the energy application zone.

The feedback may be EM feedback. EM feedback may be feedback indicativeof the EM response of the object, the energy application zone, or both,to the applied EM energy. EM feedback may include power measurements,processed to obtain, for example, absorbability indicators, scatteringparameters, and/or input impedances. For example, EM feedback mayinclude any value obtainable from a network analyzer.

FIG. 6 is a flowchart of a method 700 for applying RF energy accordingto embodiments of the invention.

In step 702, an amount of energy to be supplied at each of a pluralityof MSEs may be determined. In step 704, an energy application schedulemay be determined (e.g., based on feedback from the energy applicationzone or any calculations derived therefrom). In step 706, energy may besupplied according to the amounts of energy determined in step 702 andenergy application schedule determined in step 704. In step 708, astopping criterion may be checked, and if met, energy application mayend (710). In some embodiments, a power supply protocol may be selectedfor each energy application event. In some embodiments (not shown),steps 702, 704, and 706 may repeat several times prior to execution ofstep 708. In some embodiments, steps 702-706 may be repeated a pluralityof times while processing the object—for example: until a stop signal isreceived, e.g., from a user interface.

If the stopping criterion is not met (step 708: NO), energy may beapplied once again. In some embodiments (not shown) the energy may beapplied again with the same determined amounts of energy and/or powerapplication schedule. In some embodiments, the amounts of energy may bere-determined before energy application takes place again. Additionally,or alternatively, an energy application schedule may be re-determinedbefore energy application continues. When the stopping criterion is notmet, control may return to step 702, and both amounts of energy andenergy application schedules may be re-determined.

Determining the amount of energy in step 702 may include reading theamount of energy from a pre-programmed lookup table, receiving theamount of energy via an interface, calculating the amount of energyaccording to preprogrammed procedures, or in any other manner whichallows determining amounts of energy.

In some embodiments, determining the amount of energy may includereceiving, (e.g., from one or more detectors), power measurement resultspertaining to power detected to be emitted into cavity 10 (or energyapplication zone 9) by the one or more radiating elements and powerdetected to exit cavity 10 or zone 9. Determining the amount of energymay further include estimating or determining a value indicative ofenergy absorbable in the object, (which, for brevity, may be referred tobelow as an absorbability indicator or, in acronym, AI) and determining,based on this value, an amount of energy. Determining a value indicativeof energy absorbable in the object may include calculation based on suchpower measurements results or other feedback signal(s).

Determining an amount of energy based on an AI may include searching alookup table, where energies may be associated with AI values,evaluating the value of a mathematical function of AI, and/or evaluatingthe value of a function of AI and one or more other variables.

In some embodiments, the amount of energy determined may decrease as theAI increases. For example, in some embodiments, the amount of energy Emay be determined by evaluating the function E=E₀/AI, where E₀ may be apreprogrammed value, a value received via an interface, or a valuedetermined in any other manner and AI may be determined from powermeasurement results as discussed above. In some embodiments, otherfunctions may be used, for example, E=E₀e^(−AI/A) ⁰ , where the value ofA₀ may be determined in any of the ways that E₀ may be determined, asdiscussed above. Other functions of AI may also be used, for example,linear functions, higher polynomials (of order 2 or greater),trigonometric functions, step-functions, or any other kind of function.It was found that decreasing functions, e.g., function that inverselyrelate to AI, may be preferred for achieving uniform heating.

In some embodiments, the functions may depend on the value of AI, forexample, for some values of AI—one function may be used, and for othervalues of AI—another function may be used. For example, in someembodiments, frequencies may be classified to on-peak frequencies (at ornear which the AI has a local maximum when plotted against thefrequency) and off-peak frequencies (away of local maximums in the AI).Another example of a way to distinguish between on-peak and off-peakfrequencies, is to identify frequencies characterized by AI valueshigher than a threshold as on-peak frequencies, and frequenciescharacterized by AI values below the threshold as off-peak frequencies.Determination of energy at on-peak frequencies may be in accordance witha different function than at off-peak frequencies. For example, they mayboth be determined using exponential functions, but with differentvalues of A₀ and/or of E₀. In another example, energies to be applied tonon-peak frequencies may be determined using a liner function; andenergies to be applied to non-peak frequencies may be determined using ahigher polynomial function.

According to some embodiments, there is only a single radiating element,and the determined amount of energy is supplied to that radiatingelement. In some embodiments, there are two or more radiating elements,and each emits radiation at a different frequency to minimizeinteractions between them; and the amount of energy supplied to each maybe determined independently of the amount of energy supplied to theother. In some embodiments, there are two or more radiating elements;and the amount of energy supplied to each may be determinedindependently of the amount of energy supplied to the other.

In some embodiments, there are two or more radiating elements that emitat the same frequency, for example, at a given phase difference betweenthem (e.g., 0°, 90°, or any other phase difference value). In thesecases, the amounts of energy supplied to one may be determinedconsidering the amount of energy supplied to the other. In someembodiments, the relation between the amounts of energy supplied to eachof the two or more radiating elements may be predetermined (for a givenMSE), and the determined amount of energy may be distributed between thevarious radiating elements in accordance with this predeterminedrelation.

In step 704, one or more energy application schedules may be determined.Determining the energy application schedules in step 704 may includereceiving the energy application schedule via an interface, determiningthe energy application schedule according to preprogrammed procedures,selection of an energy application schedule by a user via a userinterface, or in any other manner.

In some embodiments, determining the energy application schedules may bebased on absorbability indicator values at one or more of the MSEs.These absorbability indicator values may be obtained, in someembodiments, during determination of the amounts of energy in step 702.In some embodiments, the amounts of energy to be supplied at a pluralityof MSEs may be determined before an energy application schedule may bedetermined or selected.

The determination of an energy application schedule may be, for example,according to a preset energy application schedule preprogrammed to theprocessor. In another example, the determination of energy applicationschedule may be based on amounts of energy determined to be applied. Forexample, in some embodiments, an intermission of a predetermined periodmay be applied after application of each predetermined amount of energy.For example, a 5 ms intermission may be determined to occur after each 1kJ of energy is supplied. In another example, an intermission may bedetermined according to absorbed energies, e.g., a 10 ms (or any otherpredetermined length) intermission may be determined after each 1 kj ofenergy is absorbed. Absorbed energy may be estimated as discussed above,as a multiplicative product of supplied energy by absorbabilityindicator, and may be determined even before commencement of energyapplication.

In some embodiments, absorbed amounts of energy expected to be absorbedduring each energy application event may be obtained before energyapplication. Then, it may be possible to know in advance at which energyapplication event the absorbed energy is to meet a given criterion.Thus, energy application intermissions may be determined based on valuesof energy expected to be absorbed. Alternatively or additionally,intermissions may be determined based on amounts of energy alreadyabsorbed.

In some embodiments, the determined energy application schedule mayinclude an order of the MSEs, at which energy is to be applied. Suchdetermination may be, in some embodiments, based on EM feedback from theenergy application zone or any calculation thereof, for example, basedon Al values. For example, MSEs may be grouped as described above, andan order of the energy application events may be determined such thatenergy application shifts from one group to another, and the number ofconsecutive energy application events, in which energy is applied atMSEs that belong to the same group, is limited. For example, the energyapplication schedule may include an order wherein no two consecutiveenergy application events include energy application at MSEs that belongto the same group,

In some embodiments, the energy application order may be determinedindependently of EM feedback from the energy application zone, forexample, based on instructions provided via a GUI. Additionally oralternatively, intermissions may be determined based on EM feedback andthe predetermined order. For example, in some embodiments, the order ofMSEs at which energy is to be applied may be predetermined such thatconsecutively applied MSEs are expected to heat differing portions ofthe object, or expected to be included in different AI peaks. Forexample, if AI peaks are known to be of a certain breadth, e.g., 20 MHzor less, the energy application schedule may include applying energy atsteps of comparable breadth, for example, 20 or 25 MHz. To ensure thatall MSEs are covered, MSEs that were omitted at first, may be applied ina subsequent energy application cycle. This may result in an irregularenergy application schedule as described above, for example, in relationto Tables 2 to 4.

In some embodiments, energy application order may be predetermined, forexample, preprogrammed. In some embodiments, a preprogrammed order maybe adjusted based on EM feedback from the energy application zone.

In step 706, energy may be supplied according to the determined amountsof energy and energy application schedule.

In step 706, power may be supplied to the one or more radiating elementsto provide the amount of energy determined in step 702 according to theenergy application schedule determined in step 704. In some embodiments,energy may be applied in only a sub-set of the MSEs for which energy wasdetermined. For example, in some embodiments, the energy determined tobe supplied at some of the MSEs may be 0 (zero), or below somepredetermined limit, and thus, power may be not applied at these MSEs.In some cases, other considerations may be applied not to supply powerat an MSE for which power application was determined and/or energyapplication schedule was determined. These considerations may be, forexample, hardware considerations (e.g., if the hardware is incapable ofsupplying energy at these MSEs), or any other consideration, forexample, the wish to omit energy application at frequency bands thathave a quality factor above some lower threshold, or an AI above somelower threshold.

In some embodiments, after energy is supplied at all the MSEs in thesubset of MSEs at step 706, a stopping criterion may be checked in step708. For example, the stopping criterion may include a predeterminedtotal amount of energy to be supplied to radiating elements, and if thetotal amount of energy supplied in practice is smaller than thepredetermined amount, the stopping criterion is not met. In anotherexample, the stopping criterion may be a total amount of energy that maybe absorbed in the object. In such embodiments, an estimate of the totalamount of energy absorbed by the object may be determined (e.g., bymultiplying supplied amounts of energy with corresponding values of AI,and summing over all the energy application events that occurred so farin the energy application process), and if smaller than thepredetermined amount, the stopping criterion is not met. Other stoppingcriterions may also be used, and the invention is not limited to anykind of stopping criterion.

If the stopping criterion is met, energy application may stop (710). Inother cases, control may return to step 702 and energy application maybe continued in accordance with steps 702, 704, and 706 until thestopping criterion is met.

In some embodiments, stopping criterion may be determined based oninstructions from outside the apparatus, which may be provided via aninterface, for example, via a GUI or via a reader of a data carrier. Thedata carrier may be, for example, a machine readable element, e.g. abarcode, an RFID, etc.

Each energy application schedule may provide a time distribution ofpower supply during an energy application event.

According to some embodiments of the invention, there may be provided amethod for applying EM energy to an object at a plurality of modulationspace elements (MSEs). In the method, energy may be applied at differentMSEs according to different energy application protocols. The protocolsmay be associated with the MSEs according to rules that may changeduring operation. In some embodiments, at least two rules may be used,and each may be associated with a different subset of the modulationspace elements.

In some embodiments, the rules may dictate associating MSEs with energyapplication protocols based on functions that depend on a parameter,e.g., on a threshold value, and differ from each other by the value ofthe parameter.

For example, in some embodiments, according to each rule, a first energyapplication protocol may be associated with MSEs showing AI values belowa threshold, and a second energy application protocol may be associatedwith MSEs showing AI values above the threshold, and the rules maydiffer from one another by the value of the threshold.

In another example, each rule includes two threshold values, and threedifferent energy application protocols may be associated to MSEsaccordingly. For example, a first energy application protocol may beassociated with MSEs showing AI values below a first threshold; a secondenergy application protocol may be associated with MSEs showing AIvalues above a second threshold, higher than the first; and a thirdenergy application protocol may be associated with MSEs showing AIvalues above the first threshold and below the second threshold. Therules may differ from one another by the value of the first thresholdand/or by the value of the second threshold.

In some embodiments, a plurality of grouping rules may be available, andthe method may include selecting among them. In the latter example, theselection may be selecting a pair of threshold values from a pluralityof available pairs.

An energy application protocol may be a formula that determines anamount of energy to be applied at an MSE, based on some value associatedwith the MSE. The value may be derivable from EM feedback received fromthe energy application zone. For example, the value may be a valueindicative of energy absorbable in the object, also referred to hereinas absorbability indicator (AI).

Some exemplary energy application protocols are provided in FIGS. 7A-7C.FIGS. 7A-7C include graphs illustrating formulas for determining amountsof energy based on values of a parameter, in accordance with someembodiments of the invention. Each of the illustrated formulas may be anenergy application protocol.

In the graphs of FIGS. 7A-7C the horizontal axis is designated with thegeneric indicator “X” to indicate that in different protocols thehorizontal axis may represent different parameter, (for example, DR, Δρ,reflection coefficients or ratios, transmission coefficients or ratios,ratios between one or more coefficients, input impedances, scatteringparameters, absolute value of each of the above, phase of each of theabove (if applicable), etc.)

In FIG. 7A, three exemplary energy application protocols are graphicallypresented. The graphs are linear and constant, and dictate applicationof the same amount of energy at each MSE, regardless of the value of theparameter X. For example, line 802 presents an energy applicationprotocol, according to which an amount of energy equal to E₃ is appliedat each MSE; line 804 presents an energy application protocol, accordingto which an amount of energy equal to E₂ is applied at each MSE; andline 806 presents an energy application protocol, according to which anamount of energy E₁ is applied at each MSE.

In FIG. 7B, four exemplary energy application protocols are graphicallypresented. The shown graphs are linear. Lines 808, 810, and 812 are allincreasing, which means that according to the energy applicationprotocols they represent, more energy is applied to MSEs associated withparameters of higher value. Line 814 exemplifies an energy applicationprotocol, according to which less energy is applied to MSEs associatedwith an X parameter of larger value.

FIG. 7C shows graphical representations of three energy applicationprotocols, 816, 818, and 820, according to which, the amount of energyto be applied non-linearly decreases as the value of X increases. Insome embodiments, line 816, 818, and/or 820 may represent a functionhaving the form E₀/X, wherein E₀ is some constant amount of energy, tobe applied at MSEs, associated with an X value of 1. In someembodiments, the non-linear relationship between applied energy and thevalue of the parameter X may be different, for example, exponential. Forexample, energy application protocol as represented by lines 814, 816,818, and 820 may be used when wishing to apply energy at MSEs inverselyrelated to the absorbable energy value at the corresponding MSE.

In some embodiments, an energy application protocol may definecorrespondence between values of the X parameter and the amount ofenergy to be applied, and this correspondence does not follow any simplemathematical form. For example, the values may be determinedarbitrarily, randomly, based on experiments, etc.

FIG. 8 is a graphical presentation of an exemplary grouping rule, forgrouping MSEs. According to the depicted rule, the parameter thatdetermines the grouping is an absorbability indicator. In otherembodiments, this parameter may be any other parameter derivable from EMfeedback, as discussed above in relation to parameter X in FIGS. 7A-7C.In some embodiments, the MSEs may be grouped according to one parameter,and the energy application protocol may determine the amount of energyto be applied according to the value of a second parameter, which may bedifferent from the first. In some embodiments, the first and secondparameters may be the same.

According to the grouping rule depicted in FIG. 8, at MSEs associatedwith an absorbability indicator having a value between 0 and a firstthreshold (T1), energy may be applied according to energy applicationprotocol 806 of FIG. 7A; at MSEs associated with an absorbabilityindicator having a value between T1 and a second threshold (T2), energymay be applied according to energy application protocol 816 of FIG. 7C;and at MSEs associated with an absorbability indicator having a valuebetween T2 and 1, energy may applied according to energy applicationprotocol 802 of FIG. 7A.

FIG. 9 is a graphical representation of the amounts of energy that maybe applied to different MSEs using the rule depicted in FIG. 8 and theenergy application protocols depicted in FIGS. 7A and 7C.

In practice, in order to determine the amount of energy to be applied ata given MSE, the processor may first select a grouping rule and thengroup the MSEs according to the rule. The processor may further selectan energy application protocol for each group. Once an energyapplication protocol is selected for an MSE, the amount of energy to beapplied at that MSE may be determined based on the energy applicationprotocol. The timing, according to which the determined amounts ofenergy may be applied at differing energy application events may bedetermined based on an energy application schedule, and the timing atwhich power is supplied to each of the radiating elements during anenergy application event may be determined according to one or moreselected power supply protocols.

In some embodiments, the grouping rule may change during processing. Forexample, in a first sweep, energy may be applied as depicted in FIG. 9,with T1 and T2 having the values of 0.3 and 0.7, respectively, and in asecond sweep, energy may be applied as depicted in FIG. 9, with T1 andT2 having the values of, for example, 0.5 and 1.0, respectively. In someembodiments, the grouping rule may change according to a predeterminedsequence. In some embodiments, the grouping rule may change whenever apredetermined event occurs, for example, whenever a predetermined amountof energy is applied since the last rule change, whenever apredetermined amount of time has elapsed since the last rule change,etc. In some embodiments of the invention, there may be two kinds ofenergy application events: sensory events and processing events. Thesensory events may be energy application events, in which the amount ofenergy applied and/or the power level at which energy is applied areused for gathering the EM feedback. The power level at which energy isapplied during sensory events may be small enough not to affect thedielectric properties to be sensed. Processing events may be events,applied in order to process an object, for example by heating. The powerlevel applied during processing events may be much larger than thatapplied during sensory events. Alternatively or additionally, the powerapplication duration may be much larger during processing events thanduring sensory events.

In some embodiments, energy application events may be arranged insweeps: sensory sweeps and processing sweeps. A sensory sweep may be anyprocess that includes consecutive sensory energy application events atmultiple MSEs. During a sensory sweep, EM feedback may be collected tobase determination of amounts of energy to be applied to each of themultiple MSEs. The determined amounts of energy may be applied duringprocessing energy application events, which may be arranged in aprocessing sweep. In some embodiments, each two processing sweeps may beseparated by one sensory sweep.

In some embodiments of the invention, the order of energy applicationevents in a processing sweep is irregular. In some embodiments, energyapplication order within a processing sweep may include back-and forthchanges along an MSE dimension, which may result in an irregular order.For example, a processing sweep may include energy application at an MSEof a first group (e.g., a sub-band of frequencies), then at MSEs of oneor more second groups, and only then at another MSE of the first group.In some embodiments, a processing sweep may include energy applicationat one MSE from each of two or more groups before energy is appliedagain at another MSE of the first group. Table 5, below, provides anexample of such an order of energy application events.

TABLE 5 Event No. Frequency  1 800.0  2 810.0  3 820.0 . . . . . . 11900.0 12 800.5 13 810.5 14 820.5 . . . . . . 22 900.5 23 801.0 24 802.025 803.0 . . . . . . 33 901.0 209  809.5 210  819.5 211  829.5 . . . . .. 219  909.5

Table 5 describes an order of 219 energy application events in aprocessing sweep according to an embodiment of the invention. In theembodiments described in Table 5, energy is applied once at eachsub-band, and then at other frequencies of the same sub-bands. The firstsub-band is between 800 and 809.5, the second—between 810 and 819.5,etc. After energy is applied once at each sub-band (i.e., after energyapplication events No. 1, 2, 3, . . . 11), energy is applied again inthe first sub-band, but in a different frequency (800.5, in event #12,compared to 800.0 in event #1).

In the foregoing Description of Exemplary Embodiments, various featuresare grouped together in a single embodiment for purposes of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed invention requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the followingclaims are hereby incorporated into this Detailed Description, with eachclaim standing on its own as a separate embodiment of the invention.

Moreover, it will be apparent to those skilled in the art fromconsideration of the specification and practice of the presentdisclosure that various modifications and variations can be made to thedisclosed systems and methods without departing from the scope of theinvention, as claimed. For example, one or more steps of a method and/orone or more components of an apparatus or a device may be omitted,changed, or substituted without departing from the scope of theinvention. Thus, it is intended that the specification and examples beconsidered as exemplary only, with a true scope of the presentdisclosure being indicated by the following claims and theirequivalents.

What is claimed is:
 1. A method of applying electromagnetic (EM) energyto an object at a plurality of modulation space elements (MSEs), themethod comprising: grouping, with a processor, a number of the pluralityof MSEs into at least a first subset and a second subset according to afirst grouping rule; associating, with the processor, a first EM energyapplication protocol with the first subset and a second EM energyapplication protocol with the second subset; applying EM energy at MSEsof the first subset according to the first energy application protocoland at MSEs of the second subset according to the second energyapplication protocol; and after the applying: grouping, with theprocessor, the number of the plurality of MSEs into a third subset and afourth subset according to a second grouping rule; associating, with theprocessor, a third EM energy application protocol with the third subsetand a fourth EM energy application protocol with the fourth subset; andapplying EM energy at MSEs of the third subset according to the thirdenergy application protocol and at MSEs of the fourth subset accordingto the fourth energy application protocol.
 2. The method of claim 1,further comprising: associating each MSE with a value of anabsorbability indicator, wherein at least one of the grouping rulesdictates grouping according to values of the absorbability indicator. 3.The method of claim 1, further comprising: associating each MSE with avalue of an absorbability indicator, wherein the grouping rules includethreshold values and dictate grouping according to the values of theabsorbability indicator in reference to the threshold values.
 4. Themethod of claim 3, wherein the grouping rules differ from one another inthe threshold values.
 5. The method of claim 1, wherein the EM energy isradio frequency (RF) energy.
 6. An apparatus for applyingelectromagnetic (EM) energy to a load in a cavity at a plurality ofmodulation space elements (MSEs), the apparatus comprising: at least oneprocessor; and a memory including instructions, that when executed bythe at least one processor, cause the processor to perform operationsincluding: grouping a number of the plurality of MSEs into at least afirst subset and a second subset according to a first grouping rule;associating a first EM energy application protocol with the first subsetand a second EM energy application protocol with the second subset;causing a power source to apply EM energy at each of the MSEs groupedinto the first subset according to the first EM energy applicationprotocol and at each of the MSEs grouped into the second subsetaccording to the second EM energy application protocol, in response tosignals generated by the processor; grouping the number of the pluralityof MSEs into a third subset and a fourth subset according to a secondgrouping rule; associating a third EM energy application protocol withthe third subset and a fourth EM energy application protocol with thefourth subset; and after the EM energy is caused to be applied accordingto the first and the second energy application protocol, causing a powersource to apply EM energy at each of the MSEs grouped into the thirdsubset according to the third EM energy application protocol and at eachof the MSEs grouped into the fourth subset according to the fourth EMenergy application protocol, in response to signals generated by theprocessor.
 7. The apparatus of claim 6, wherein the operations furtherinclude associating each of the plurality of MSEs with a value of anabsorbability indicator, and at least one of the grouping rules dictatesgrouping according to values of the absorbability indicator.
 8. Theapparatus of claim 6, wherein the operations further include associatingeach of the plurality of MSEs with a value of an absorbabilityindicator, and wherein the grouping rules include threshold values anddictate grouping according to the values of the absorbability indicatorin reference to the threshold values.
 9. The apparatus of claim 6,further comprising: wherein the operations further include causingapplication of energy by controlling the source of RF energy.
 10. Theapparatus of claim 9, further comprising: a plurality of antennasconfigured to receive RF energy from the source of RF energy and applyat least a portion of the RF energy so received to a resonant cavity.11. The apparatus of claim 6, wherein the apparatus comprises a resonantcavity.
 12. The apparatus of claim 6, further comprising: a detectorconfigured to supply to the at least one processor with data fordetermining a value of an absorbability indicator.
 13. The apparatus ofclaim 11, further comprising: a detector configured to supply to the atleast one processor with data for determining a value for theabsorbability indicator.
 14. An apparatus for applying electromagnetic(EM) energy to a load at a plurality of modulation space elements(MSEs), the apparatus comprising: a processor including an electricalcircuit; and a memory including instructions, that when executed by theat least one processor, cause the processor to perform operationsincluding: grouping a number of the plurality of MSEs into at least afirst subset and a second subset according to a first grouping rule;associating a first EM energy application protocol with the first subsetand a second EM energy application protocol with the second subset;generating, with the processor, control signals to control a powersource to apply EM energy at each of the MSEs grouped into the firstsubset according to the first EM energy application protocol and at eachof the MSEs grouped into the second subset according to the second EMenergy application protocol; grouping the number of the plurality ofMSEs into a third subset and a fourth subset according to a secondgrouping rule; associating a third EM energy application protocol withthe third subset and a fourth EM energy application protocol with thefourth subset; and after the EM energy is caused to be applied accordingto the first and the second energy application protocol, generating,with the processor, control signals to control the power source to applyEM energy at each of the MSEs grouped into the third subset according tothe third EM energy application protocol and at each of the MSEs groupedinto the fourth subset according to the fourth EM energy applicationprotocol.
 15. The apparatus of claim 14, wherein the operations furtherinclude associating each of the plurality of MSEs with a value of anabsorbability indicator, and at least one of the grouping rules dictatesgrouping according to values of the absorbability indicator.
 16. Theapparatus of claim 14, wherein the operations further includeassociating each of the plurality of MSEs with a value of anabsorbability indicator, and wherein the grouping rules includethreshold values and dictate grouping according to the values of theabsorbability indicator in reference to the threshold values.
 17. Theapparatus of claim 14, further comprising: wherein the operationsfurther include causing application of energy by controlling the sourceof RF energy.
 18. The apparatus of claim 17, further comprising: aplurality of antennas configured to receive RF energy from the source ofRF energy and apply at least a portion of the RF energy so received to aresonant cavity.
 19. The apparatus of claim 14, wherein the apparatuscomprises a resonant cavity.
 20. The apparatus of claim 14, furthercomprising: a detector configured to supply to the at least oneprocessor with data for determining a value of an absorbabilityindicator.
 21. The apparatus of claim 19, further comprising: a detectorconfigured to supply to the at least one processor with data fordetermining a value for the absorbability indicator.